A mechanism for continuously adjusting engine valve lift is used for solving the problem of matching between the engine valve lift and engine running conditions. The mechanism comprises an adjusting arm assembly, a swinging arm, a connecting arm, a rocking arm, an eccentric shaft and a motor, the adjusting arm assembly is hinged to the connecting arm through an adjusting pin, the connecting arm is fixedly assembled with the swinging arm which is assembled with the rocking arm, two ends of the rocking arm are assembled with a valve and a hydraulic tappet respectively, the eccentric shaft is connected with a motor output shaft, and a set of eccentric wheel is arranged on the eccentric shaft. The mechanism is characterized in that a set of eccentric shaft adjusting plate is further arranged, the eccentric shaft adjusting plate is assembled with the eccentric shaft through a reciprocating motion support, a first working face matched with the eccentric wheel and a second working face matched with the adjusting arm assembly are arranged on the eccentric shaft adjusting plate, and the second working face is a circular-arc working face. By the mechanism, requirements on air inflow of an engine under different working conditions are met, the number of parts is reduced, and manufacturing cost of the parts is lowered.