An effective depth measurement method based on desktop vision system (DVS) with high precision is proposed. For this purpose, rectification techniques for stereo image pairs are proposed and derived, which mainly consist of geometric distortion correction, reprojection transformation by central projection, zooming transformation, vertical translation transformation and brightness and color correction. The reprojection transformation can change the stereo image pairs captured by a binocular converged camera system with different camera intrinsic parameters into those captured by binocular parallel camera system with the same camera intrinsic parameters (except geometric distortion coefficient). For depth measurement, firstly, the stereo image pairs captured by a DVS are rectified and corrected into perfect ones. And then, horizontal parallax of the corresponding points of interest is gotten by stereo matching. Finally, the depth information of the spatial point of interest is calculated based on horizontal parallax and the parameters obtained by camera calibration. Experimental results show that the proposed depth measurement method is simple and practical, and the relative error is demonstrated for depth measurement of the near distant objects to be no more than 0.31%.