Abstract: In order to measure the vertical target coordinates of the large target surface,a coordinate measurement method with laser screen target was presented with four 90° fan-shaped lasers as light sources,and a high-sensitivity photodiode array as the receiver.When bullets fly through the rectangular laser screen,formed by the intersected light from the four lasers,they will block part of the laser in the x and y directions respectively,and thus corresponding signal produces from the photodiodes.The impact coordinates can be obtained by acquiring and processing the signal.Finally the coordinates of the bullet were tested in active experiments.The results show that this vertical target system has the characteristics of high precision and high sensitivity.