The invention discloses a method of improving tracking accuracy for a target tracking system, which includes the following steps: placing a planar mirror at the back of a diaphragm of the target tracking system and attached to the edge of the photosensitive surface of a photosensitive device, placing the identical planar mirrors on two sides or the periphery of the target tracking system in the same way, additionally arranging a semitransparent and semi-reflective mirror or a mirror with an original system adopting wavelength transmission and not using wavelength reflection in front of the diaphragm, imaging the whole field of view on another image surface through a light path, and determining an area image points located in according to positions of the image points on the image surface; and substituting the position information in the original system, and calculating high-accuracy image point coordinate information by matching data of the position information and the original system. The method can improve system accuracy for several times based on the prior art, is relatively easy to achieve especially for systems of one-dimensional motion or two-dimensional motion, and can obtain high accuracy improvement with low cost.