Aiming at the difficulty of target matching between two kinds of sensors in the fusion of radar and video data in the process of highway vehicle tracking, a highway vehicle tracking method based on target trajectory similarity matching was proposed. Firstly, the radar data is converted to the dimension of video data by projection transformation. Secondly, curve fitting algorithm is used to interpolate discrete trajectory points into continuous trajectory curves. Finally, the similarity between the trajectory curve projected on the image of the radar detection target and the trajectory curve of the video detection target is calculated, and the matching relationship between the radar detection target and the video detection target is obtained by screening the similarity matrix. Comparative experiments were carried out with vehicle data collected in real scenarios on highways. The results show that the average success rate of target matching in the expressways is 94.71%, which is 3.01% and 3.69% higher than that of other similar methods. The proposed method can effectively filter false targets and is more suitable for vehicle tracking in highway scenarios.