To reduce the costs of an impact point measurement, a measuring method for impact points of projectiles was proposed.A Z-shaped light screen target containing three light screens was made up of a column laser source, a optical detector and two pieces of mirrors to measure the impact points and the velocities of projectiles.The velocity and the impact point position in the horizontal direction were obtained by a time measurement and the impact point position in vertical direction was obtained by an optical detector.The principle was analyzed and the light source, optical detector, the feature of impact signal, available detector area, and the firing rate were discussed.A principle experiment with a steel ball was carried out on a smooth plane table using a laser pen, two pieces of mirrors and a photodiode circuit.The experiments show that the absolute errors of position measurement by the proposed method are 0.1 to 1 mm as compared with that by a high speed camera.Furthermore,the relative errors of velocity measurement are between 0.02% to 0.2% as compared with that of a traditional method.The experimental results indicate that the method is feasible and easy to realize in a low cost.