Abstract: COVID-19 epidemic continues to spread around the world till these days, and it is urgent to develop more safe and effective new drugs. Due to the limited P3 biosafety laboratories for directly screening inhibitors of virulent viruses with high infectivity, it is necessary to develop rapid and efficient screening methods for viral proteases and other related targets. The main protease (M^pro), which plays a key role in the replication cycle of SARS-CoV-2, is highly conserved and has no homologous proteases in humans, making it an ideal target for drug development. From two different levels, namely, molecular level and cellular level, this paper summarizes the reported screening methods of SARS-CoV-2 M^pro inhibitors through a variety of representative examples, expecting to provide references for further development of SARS-CoV-2 M^pro inhibitors.