Abstract: A batch of muti-aperture diaphragm arc designed.Laser beam passes through muti-aperture diaphragm after expanded, and then,multi-beam coherent lasers are attained.Based on multi-beam laser interference theory,by changing mutiaperture diaphragm,the coherent combining intensity distribution of multi-beam laser is observed.The results show that the decrease of duty ratio of output elements will reduce the enegy of the central lobe,and increase the number of side lobes.It is found that the far-field interference intensity distribution is best when coherent elements is on triangle array.The experiment results provide the references for high power laser coherent combining.