According to the fact that the linear imaging model cannot explain the lens distortion,and to overcome the problem that the ordinary calibration methods are not suit for the change of height and angle, based on the pin-hole model and the previous distortion correction, this paper builds up a mirror coordinates system to study the reflection relation of pixel and angle. By using trigonometric functions and distortion coefficient,the height parameter and angle parameter are introduced into the model,and then the non-linear model is obtained. Finally, under different kinds of situation, comparing with Tsai’s method, the algorithm validity is verified. After changing the camera angle and height, the algorithm, which does not require re-calibration, is still with good accuracy and robustness. Thus, the algorithm can be applied to the engineering field.