To study the impact of marine environmental corrosion on the seismic performance of wind power towers，a 3 MW offshore wind power tower was used as an example. Based on a universal finite element analysis platform，wind power tower analysis models before and after corrosion were established，and time history analysis was used to study the collapse mechanism of the wind power tower during earthquakes. Through modal analysis，the impact of marine corrosion on the frequency and mode of vibration of structures was studied. Three natural ground motions (two far-field motions and one near-field motion) were selected，and time history analysis was used to study the deformation and damage evolution of the wind power tower. The collapse mechanism of the wind power tower was revealed based on the calculation results. The research results show that marine corrosion has a relatively small impact on the frequency and mode of vibration of the wind power tower. Under the action of near-field or short-term earthquakes，marine corrosion will not significantly change the collapse mechanism of the wind power tower. Under the action of long-term earthquakes，the corroded parts of the wind power tower will be damaged first，which will trigger higher-order modes of vibration and cause significant changes in the seismic damage and collapse mechanism of the wind power tower.