Abstract: In laser tailored blank welding for three-dimensional joint, the welding robot that follows a preprogrammed path assisted with clamping equipment is not often able to guarantee a sufficient weld seam quality. In order to improve suitability of laser welding robot, the welding torch pose need to be adjusted during welding process. The torch is requested to be aligned at right angles to the joint surface which means in the direction of normal vector of joint. In this paper, measuring equipment is designed and a new method is proposed for measuring normal vector of three-dimensional joint accurately based on circle structured light with surface fitting model. Finally, the simulations are carried out to verify the proposed strategy. The simulation results are compared with conventional method based on stripe structured light with plane fitting model and demonstrate that this method has upper measurement precision, and will contribute to adjust welding torch pose accurately.