In laser heterodyne detection system, the deficiencies of non-coaxial between telescope and aiming in practical applications are analyzed, and an approach by the use of spectroscope and CCD imaging technology to focus and aim is introduced. When the spot of the telescope launch beams convergent to the target is the smallest, and the image is the clearest on CCD, the focus length is optimal; the sizes of the fields of view detected by CCD are different as the distances of target are different, but the target image and the spot location are always at the center of the field of view. So the real-time adjustment is not needed. It improves the operation and practicality greatly. Experiments are verified at last.