Abstract: Taking ZhuRong Mars rover as the research object, the sinkage mechanism of the Mars rover is analyzed based on the theory of vehicle terrainmechanism, and a sinkage determination method is presented based on the slippage ratio, current, sinkage depth and so on. The sinkage determination criteria in different conditions are formulated and the corresponding extrication strategies are proposed for ZhuRong Mars rover. The verification test results show that the slippage ratio is 61.25% and the driving current is 1.9 A in the case of critical sinkage. The rover can't drive away directly when reaching the critical sinkage value, but ZhuRong Mars rover can effectively extricate itself through peristalsis of its active suspension. The research results can provide test data and reference for the in-orbit usage strategy of ZhuRong Mars rover.