Abstract: In order to obtain a better echo signal for ultrasonic testing of curved workpieces, the incident direction of the sound beam is required to be consistent with the normal direction of the outer surface of the curved workpiece. The existing method usually knows the surface CAD model in advance, and detects the surface with known contour, which makes the system's flexibility and applicability poor. Aiming at the above problems, a probe alignment algorithm based on laser measurement is proposed.The principle of the method is:the laser measurement system recognizes the position and posture information of the measurement point on the surface to be measured, and then sends the acquired measurement point information to the controller of the manipulator. After the robot control system obtains the measurement point information, it sends the probe pose adjustment information to the corresponding robot arm controller according to the alignment control strategy to realize the probe alignment of the measurement point. By exploring the relationship between different incident angles and the time-domain eigenvalues of the echo signal, the effectiveness of the method is verified.