Laser transmission joining of fiber reinforced polyamides (FRPA) has potential application in industry. Based on a central composite rotatable design, comprehensive experiments of laser transmission joining of FRPA are carried out by a diode continuous laser source. The microscopic cross-section observation shows that the joining area is good. The effect of process parameters on the joint quality is analyzed by processing of the experimental data. Finally, mathematical models between the process parameters, the lap-shear strength and the joint width are determined by response surface methodology. The results show that the process parameters of laser transmission welding play a significant role in determining the joint quality; and the predicted data of the models are in good agreement with the experimental results. So this study could provide an effective instruction to choose the reasonable process parameters for enhancing the joining efficiency.