Abstract: A three dimensional quasi-state numerical model of fluid flow,heat transfer process in the melted pool for composite coating was developed,and the temperature profile,velocity profile in laser pool and pool geometry were successfully calculated. Affects of laser power on heat transfer and fluid flow in a laser pool and the pool geometry were investigated. Numerical results show that there is only one pool in the substrate when laser power is 750W,and there are two separated pools when laser power is 1400W for the composite coating system of Ti-Al(30%) alloy. It is decided by the thickness of the composite coating,whether the composite coating firstly is melt or Al substrate. The experiment of laser remelting was performed for composite coating system,the separated pools have been observed,and the pool geometry was agreement with that calculated.