Abstract: The process test and theoretical analysis were conducted on laser welding in space engine simulation parts. Results show that,under the premise of reaching a certain weld depth,the porosity increases with the increase of the laser power,the decrease of the welding speed,the negative increase of the defocus amount,the positive change of the incident angle,and the lateral large flow of the shielding gas.On the basis of the proven stomata characteristics,the process specification was obtained,whih is the most conducive to suppress the deep penetration of laser deep-welding. By using this specification,a number of samples of engine products were welded. Relevant tests have shown that the porosity and other properties of the weld meet the Class I requirements of the industry standard,and official products have passed the flight test.