The invention discloses hepatitis c virus NS3/4A protease, a gene and a method for detecting activity of an inhibitor. The nucleotide sequence of the gene is a nucleotide sequence shown as SEQ ID No.1 in a sequence table or the encoded amino acid sequence of the gene is the nucleotide sequence of protein shown as SEQ ID No.2 in the sequence table. According to the method for detecting the activity of the inhibitor, the defects that when a common cell screening model is used for screening medicine, the process is complex, and cost is high are avoided, and the advantages of being clear in medicine acting mechanism, low in cost, high in efficiency, high in sensitiveness and capable of achieving high-throughput screening are achieved.