Abstract: Taking laser peak power, welding speed, pulse width and defocusing quantity as optimization process parameters, the tensile strength, elongation, welding depth and weld width of the welded joint are optimized. The pulse laser welding process parameters optimization of 6061 aluminum alloy of multi-objective is carried out by combining orthogonal test and the analysis theory. The data samples are obtained by orthogonal test, and the data analysis is used to optimize the process parameters by the set pair analysis method. First, we determine the identity degree, degree of opposites and closeness degree of single process objectives between ideal solutions. Then we use the weight sum of nearness of single process objectives to represent the closeness of comprehensive process objective. Finally, the best process parameters are determined according to the average closeness of the comprehensive process objective of the process parameters in different process levels. The optimized results are as follows: laser power 3.5 kW, welding speed 2.4 m/min, pulse width 4.0 m/s, defocusing-1 mm.