The position difference measurement for targets in the same-frame film is an important shooting range test. In this paper, a monocular videometric method was proposed to measure the targets position difference in the same-frame film. First, a target in the sameframe film was tracked using a monocular camera and its position and velocity were measured using a monocular trajectory intersection method. Then the position difference measurement method was derived between the target tracked and the new target in the same-frame film based on two hypotheses respectively that the new target was on the moving way of the tracked target and the distance between the new target and the measurement camera equal to that between the tracked target and the camera. Some simulations were performed. The results show that the monocular videometric measurement method proposed in this paper can measure the targets position difference in the sameframe film accurately.