Abstract: A series of resistance spot welding tests for TRIP600 high strength steel plate for vehicles with a thickness of 1.5 mm were carried out. The microstructure and mechanical properties of the plate were analyzed. The results show that the best welding process for TRIP600 high strength steel plate was given when relevant spot was 7.1 kA, electrode pressure was 4 410 N and welding time was 0.06 s. Both welding current and welding time had remarkable effects on the properties of welded joint. Increase of welding current and extension of welding time could effectively enhance the strength of welded joint. Shear fracture mainly occurred in the heat affected zone of welded joint, and was brittle.