An abdominal motion measurement system, which is based on point structured light, is designed to monitor the real-time movement of the patients’ abdomen along with respiratory motion. It can actively compensate the target displacement caused by respiratory and realize the relative stillness of the target in radiotherapy. The laser-point-structured measurement method, which is based on laser triangulation, can convert the abdominal movement into the translation of the laser point. Then, the abdominal movement can be calculated from the extracted pixel locations of the laser point in each captured image with the known system parameters. The experimental results show that the proposed method can obtain the position information accurately in real-time, and it has the advantages of simple structure and high precision and offers a new solution to compensate the respiratory influence in chest and abdomen radiotherapy.