Sealing side welding parameters of 6061 aluminum alloy and 316 L stainless steel welded by Nd∶YAG laser were optimized,and welding cracks,intermetallic compounds,microhardness and fracture morphology were observed and analyzed. Results show that the quality of welding joint is good when welding current is 110 A,laser pulse width is 4 ms,laser frequency is 16 Hz,welding speed is 200 mm/min,and the maximum shear force per unit length is 19.79 N/mm. The field near the crack has higher vickers hardness than other areas,and the maximum hardness is Hv701;the forms of the intermetallic compounds which mainly distributed in near the fusion line are nubby and acicular,and its iron contents decreases with the increase of the depth of fusion. Fracture mode shows the brittle characteristics with some local areas of plastic fracture in shear experiment.