Method for screening protease inhibitor

The invention provides a method for screening a protease inhibitor. The method comprises the following steps of: (1) adding a substance to be tested in protease solution to be uniformly mixed and meanwhile setting the protease solution in which the substance to be tested is not added as a blank control; (2) adding substrate protein solution into the protease solution to react so as to obtain reaction solution; (3) adding reaction end solution in the reaction solution; (4) adding ninhydrin solution to react; and (5) adding double distilled water, judging a result according to an absorbance value OD570 nm, and ensuring that a sample to be tested is positive if the absorbance of the solution of the matter to be tested is less than that of the blank control. By using the method, the protease inhibitor can be conveniently and quickly screened, a substrate is not required to be manually synthesized, the cost is low, the flexibility is high, and a new approach is provided for finding a medicament for inhibiting tumor invasiveness and metastasis.