Referring to the deformed scan image of the moving target obtained by a line-scan camera, a new method was proposed to estimate the motion parameters using a line-scan camera. The method, based on one-dimension imagery model of the line-scan camera, made use of the temporal and spatial relations of the key points on the target image to establish a serial of nonlinear functions related to the motion parameters, which transforms the estimation of the motion parameters into a problem of nonlinear optimization. In the analysis of the deformed license plate images of the moving vehicles, speed and direction were estimated. The experiment results show that, the method has good practicability and accuracy.