my country's offshore wind power market will develop rapidly in the next ten years. In view of the harsh working conditions of offshore wind power, wind power spindle bearings need higher power density, reliability and service life. This paper mainly expounds the current situation and future development direction of wind power spindle bearing technology from the aspects of bearing design, material, surface treatment and technology. 1. Offshore wind power market and development trend of large megawatt units The Global Offshore Wind Power Report 2020 released by the Global Wind Energy Council (GWEC) predicts that by 2030, the global installed capacity of offshore wind power will increase from the current 29.1GW to 234GW. Regions will be the most important markets. On September 9, 2021, the '2021 Global Offshore Wind Power Report' was released at the Port of Shoreham, UK. In 2020, the global offshore wind power installed capacity was 6.1GW, slightly lower than the 6.24GW in 2019. However, GWEC expects that 2021 will be the global offshore wind power generation. A record year for wind power installations. The report predicts that under the current wind power policy, the world will add 235GW of offshore wind power capacity in the next decade, which is equivalent to seven times the existing offshore wind power capacity. Compared with the 2020 report, this forecast has been revised up by 15%. In 2020, China achieved more than 3GW of new offshore wind power connected to the grid, becoming the world's largest offshore wind power market for the third consecutive year. The European market maintained steady growth, with the Netherlands ranking second globally with nearly 1.5 GW of new installations, and Belgium third (706 MW). According to the latest report of the International Energy Agency (IEA) and the International Renewable Energy Agency (IRENA), if the global temperature rise is to be controlled within 1.5°C, the global installed offshore wind power needs to reach 2,000GW by 2050, and the current installed capacity is not yet To 2% of this target, the projected installed capacity in 2030 is only 13% of this target. 2. The development status and technology of offshore wind power bearing technology Due to the special working conditions of offshore wind turbines, the main shaft bearing needs to be installed at an altitude of tens of meters above the sea surface. Bearing transportation, installation and replacement are extremely inconvenient and expensive. At the same time, the environment in which offshore wind power bearings are located is very harsh, including typhoons and high air humidity leading to corrosion, etc. Therefore, high performance, high reliability and long life are the qualities that spindle bearings must have. At present, wind power spindle bearings mainly rely on imports. The famous international wind power spindle bearing manufacturers mainly include Sweden SKF, Germany Schaeffler, American Timken, etc., occupying a dominant position in the global market. There is still a big gap between my country's wind power bearings and foreign ones, mainly in materials, design, surface treatment, technological level and technological equipment. 2.1 Design of offshore wind power main shaft bearings At present, the main shaft bearings in wind turbines mainly bear most of the radial force, axial force and bending moment generated by external wind in the transmission chain, and transmit stable torque to the high-speed end of the wind turbine. . Therefore, the bearing capacity, reliability and service life of the spindle bearing are very key indicators. At the same time, when the positioning end spindle bearing faces a large axial force or axial impact, its axial stiffness will determine its impact under the external force. The axial displacement will have a great impact on the stability of the force inside the gearbox. With the continuous improvement of the megawatt level of offshore wind power, whether it is a single-point support or a double-point support scheme layout, how to improve the bearing capacity, reliability and life in a limited space to a greater extent has become a great difficulty. At the same time, there are obstacles such as one-way eccentric load, system vibration, and insufficient lubrication conditions. Most of the currently installed wind turbines use the main shaft bearing support structure, and the main shaft bearings are generally divided into two-point support and three-point support arrangements. Figure 1 Representative layout of main shaft bearings 2.1.1 Technical scheme of spherical roller bearings for main shafts The locating end bearing plays an important role. It not only needs to meet the main bearing requirements of radial and axial loads, has a certain self-aligning performance (usually requires more than 0.3°), but also needs to be able to operate stably for 20 years at low cost . The existing technical solutions are as follows: 1) Internal structure optimization The existing structure of large-size spherical roller bearings is shown in Figure 2. According to the structure of the spacer, it can be divided into fixed spacer, floating spacer and no center Spacer design. Compared with the design of floating spacer and no spacer, the fixed spacer can effectively increase the axial stiffness and reduce the axial movement distance under the influence of axial force, thereby effectively reducing the influence of axial force on the gearbox.