Abstract: Polymethyl methacrylate (PMMA) and 304 stainless steel were welded by laser heat conduction joining technique, and welding quality between transparent PMMA and 304 stainless steel was investigated by orthogonal test method. Tensile test and section test were carried out, and welding results were quantitatively determined by energy density. The effects of various welding factors on tensile strength and weld width were analyzed. Experimental data were processed by the difference analysis method of orthogonal test, and optimal welding parameters of laser heat conduction welding between PMMA and 304 stainless steel were achieved. The results showed that the welding speed was the most dominant factor in determining the joint strength, and the pulse width, gas protection volume, peak power, spot diameter and pulse frequency were the 2nd to 6th effective factors.