The key technologies which based on the technology of image based distance measurement are researched for the avoidance of automobile collision. Firstly, according to the principle of relative motion and assume that the image distance measurement testbed is moved to collect images along the direction of the optical axis, and then the improved SIFT matching algorithm which is well used for image matching to obtain matching points. The world coordinates of the matching points are calculated to obtained distance value. Secondly, the validity of distance measurement principle is demonstrated by experiments. Finally, the image based distance measurement technology is applied into the automobile collision avoidance system. The error average of measurement system is 8.507 7 mm, the practicability and validity of the whole theme are proved by experiment results.