[Introduction] In this paper, strength and toughness analysis under earthquake for the whole model of offshore substation is presented, performance of offshore substation is analyzed under effect of earthquake in the design reference period different exceedance probabilities. [Method] The seismic performance was evaluated by the results from response spectrum method for strength analysis and the pushover analysis method for toughness analysis. [Result] By analyzing performance of substation jacket platform and accessory structures, the seismic performance of the structure meets the requirement of "No damage under minor earthquake, Repairable under moderate earthquake, No collapsing under major earthquake" considering sufficient safety factor. [Conclusion] It shows that the offshore substation has good seismic performance.
