Abstract: To solve the problem of the space limit when the abnormity work piece is stitched,a kind of one-side-stitching mechanism is developed based on two needles with a slider-crank mechanism and a cam gear mechanism.The mechanism can access to the work piece and stitch from only one side.The working principle and the method of design are introduced and the mathematical model of slider-crank mechanism is established.The kinematics simulation of the slider-crank mechanism is developed with MatLab.According to the result of simulation,cam gear is designed by reversal method.The data of the simulation is exact and the dimension is credible.