The invention discloses a lock fixing mechanism of a dynamic tester for an automobile trunk lock. The lock fixing mechanism is connected to the tail end of a trunk cover mechanism and comprises a pair of clamping jaws for clamping locks to be tested; the middle parts of the clamping jaws are hinged; one end of each clamping jaw is a clamping end and the other end of each clamping jaw is a driving end; a protecting plate is arranged below the clamping ends; a group of metal contacts are arranged at one side of the protecting plate; the locks to be tested are clamped between the protecting plate and a pair of clamping ends; a top block is arranged below each driving end; a tapered wedge is arranged below each top block and is connected with clamping jaw air cylinders arranged at two sides of the corresponding clamping jaw; piston rods of the clamping jaw air cylinders extend out; the tapped wedges drive the corresponding top blocks to upwards eject the driving ends of the corresponding clamping jaws, and middle hinge points are taken as pivots, so that the locks to be tested are clamped by the clamping ends. According to the lock fixing mechanism disclosed by the invention, a real automobile environment is completely simulated, and abnormal defects can be completely exposed, so that the quality of products is better controlled.