Abstract: The main effective factor of temperature field was analyzed and the calculation model of temperature field in multi-pass laser cladding was built. In the model the main consideration was given to the thermal boundary conditions and heat source. And the temperature field of three passes cladding process on plate were calculated. The temperature variations of the three points at the center of each pass were obtained. The analysis results show that the temperature variation curves of the three center points were serrate and their peak values were different. Moreover, under the multi-pass condition the lowest temperatures of the three points before their temperature ascending went up gradually during the cladding process and the trend was similar to the parabola. The results are reasonable, and could make preparations for studying the stress and strain variation.