In the process of laser engineered net shaping,in order to quickly and efficiently to obtain the information of molten pool and control it,this paper designs a CCD coaxial camera system for dual color images of the molten pool,it can accurately obtain the image information of molten pool.The computer uses the minimum bounding rectangle image processing method to obtain the molten pool width quickly and efficiently,and controlled by PID controller to adjust the laser power.The experimental shows that the CCD coaxial camera system based on dual color image and the closed loop control of molten pool width can effectively solve the problem of edge bulge and uneven width of the thin-walled workpiece under the reciprocating laser scanning.