In this paper, a self-calibration technique of the camera based on three vanishing points is introduced. This calibrating method is realized by the constrained condition among the vanishing points obtained by using three groups of in pairs orthogonal parallel lines in the nature scene. The optimization correction of the obtained vanishing points can be obtained. The experimental research has been done and the result has been compared with the traditional method. The result shows that the algorithm proposed in this paper has better application prospeet.