Rapid development of computer technology brings about emergency of interactive interpretation of remote sensing images on computer screen. It holds higher precision and can directly enter geographical information system. More attention should be paid to its low efficiency. This paper shows the method of vector trace of distinct objects in screen digitalization of remote sensing images. With equal and higher precision, the method can greatly enhance the work efficiency, and possesses the important significance to the design and development of special software for manual screen digitalization of remote sensing images.