A new seal structure of wind turbine bearing was designed,which consisted of a labyrinth seal and a rotary shaft lip type seal.Considering the variable natural conditions in operation of wind turbine,an oil seal with dustproof lip was chosen,which was made of hydrogenated nitrile rubber of antiwear,hightemperature and ozone resistance.The deformation of the bearing in the limit load condition was calculated based on ANSYS.The mathematical relationship between radial clearance and axial clearance of labyrinth seal was derived,and the clearance of labyrinth seal was determined.