The ordinary digital camera calibration has been one of the active research fields in computer vision and photogrammetry. This paper proposes a novel calibration method with ease for operation and high accuracy, as well as robustness. This method uses a micro plane grid as the calibration reference object which is photographed for a couple of images in the same direction, applies a high-precision distortion model which takes the high-order nonlinear distortion into account, and restrains the correlation effects among camera parameters so as to strengthen the convergence of the algorithm by iterative calculation of distortion coefficients and interior orientation elements in steps. The experiments demonstrate stable results and reliable accuracy of calibration is achieved by this method.