To study the evolution law of the temperature field, flow field of molten pool and the macroscopic morphology of cladding layer in the process of laser cladding, the changes of molten pool morphology and distribution of molten pool temperature and flow fields due to the variation of the corresponding parameters during the laser cladding process are studied in this paper. Energy conservation equation, apparent heat capacity method, fluid dynamics theory and moving mesh algorithm were employed to analyze the effects of laser power, scanning speed, powder feeding rate and other process parameters on the cladding layer, the law of Marangoni convection caused by the change of surface tension temperature coefficient on the macroscopic morphology of molten pool and the distribution of internal temperature field and flow field were revealed.