Abstract: The experiments on laser transmission welding of dissimilar plastic between transparent PS and PVC were carried out with clearweld additive, and the welding quality was investigated by orthogonal test.Tensile and section tests were conducted for experimental samples, and the influence of welding factors on tensile strength and weld seam size were analyzed.The optimized welding parameters are obtained by range method, which indicates the influencing parameters on welding strength are welding speed, fixture pressure, beam diameter, laser average power, laser frequency, holding time after welding.Research results are helpful to guide practical production.