Abstract: Objective The aim is to achieve high-quality welding between high-carbon high-alloy stainless steel and conventional stainless steel. Methods The study examines the influence of laser processing parameters on the macro morphology of the welds by laser welding 9Cr18MoV and 3Cr13 martensitic stainless steels. The parameters are optimized, and the mechanical properties and microstructure of welded joints are analyzed. Results The weld top width is maximum and bottom width is minimum at a defocusing amount of +1 mm. When the defocusing amount and laser power remains constant, the welding speed is negatively correlated with weld width. As the welding speed increased from 35 mm/s to 55 mm/s, both weld top and bottom widths gradually decreased. With other parameters hold constant, the laser power is positively correlated with weld width, which increases with higher power. The base material on both sides of fusion line exhibites the highest hardness. The hardness in the weld zone is relatively uniform, while the hardness in the heat-affected zone gradually decreases with increasing distance from the weld center. Conclusion The weld microstructure consists of martensite and austenite. C and Cr elements are enriched at the grain boundaries, while Fe element is enriched within the grains. Additionally, rod-like carbides precipitated at the grain boundaries. The fracture of the welded joint follows a ductile-brittle mixed mode, with the fracture location primarily in the weld zone, accompanied by minor base material loss on the 3Cr13 side.