Laser cladding is a new technology to clad metallic material to substrate. The objective of this research is to find optimized process parameters such as preheating temperature of substrate, laser power, scanning speed, spot diameter for cladding Cr18Ni8Mo2Si on 40Cr substrate. Moreover, effects of different cooling modes, cooling in temperature control box or natural environment were studied. Orthogonal experiments are used to find optimized parameters and better cooling strategy. Experimental results are analyzed through measurements of residual stress, micro-hardness, and metallic microstructure. It was observed that parts cooling in temperature control box show better qualities: smaller residual stress, less cracks or other structural defects, better microstructure, and better bonding effect. This research provides a guideline for further researches in temperature control of laser cladding and expands application to rotary die cutting machine.