Abstract: According to the existing problems of TIG weld pool three-dimensional surface measurement, the measurement method of grid structure lasers for weld pool surface reflection was put forward. CCD camera was applied to record the video image of structure lasers which are reflected by different surface. Based on that, the reflection lasers imaging of ideal convex and concave were calibrated and were analyzed respectively. The weld pool surface reflected on lasers grid which projected on the imaging plane with the different TIG welding current was further analyzed. And the concavity and convexity of weld pool free surface were studied. The results showed that us grid lasers could reveal the concavity and convexity of weld pool surface better. And with the increasing of welding current, weld pool would slowly collapse in the middle of the convex surface.