A scroll compressor with a backflow-proof mechanism. The scroll compressor comprises a slider disposed on a scroll couple, forming several enclosed spaces. The slider is raised by the working fluid in the spaces, preventing liquid leakage from a high-pressure chamber to a low-pressure chamber, when the scroll compressor starts. The slider descends when the compression ratio of the scroll compressor is exceeded. Thus, the pressure is released, and the performance of the scroll compressor is improved. The slider of the invention further comprises a floating element to prevent reversal of pressurized fluid and damage to the scroll couple.