In order to study the dynamic response characteristics of a planar multi-link mechanism with wear gap, this paper takes a seven bar linkage mechanism with two degrees of freedom as the research object, and conducts dynamic modeling and response analysis on the mechanism with wear gap. Firstly, based on the Archard wear model, a rotating pair wear gap model was developed; The rigid body dynamics equation of a planar seven bar mechanism with wear gaps was developed using the Lagrange multiplier method, and the equation was solved using the Runge–Kutta algorithm. The rigid body dynamic response and wear characteristics of the mechanism with rotating pair wear gap under different driving speeds and initial gap values were analyzed and predicted. The results indicate that a larger initial gap value and an increase in driving speed will exacerbate the wear between the surfaces of the motion pair components, leading to irregular loss of the shaft and bearing surfaces, increasing the amplitude and peak value of the dynamic response curve, making the collision trajectory at the gap more chaotic, and seriously damaging the dynamic performance of the mechanism.