A calibration method based on target features circle is proposed, which can determine the camera internal parameters based on the two different CCD images. One CCD image can be obtained in a position, and the other CCD image can be gotten by moving the target or camera to a new position. The principle of the calibration method based on one-step movement is expounded. The geometrical relationship and the criteria that the camera axis is orthogonal to the target plane are proven when the CCD image is circle. Finally, the experiment results verify that the method proposed is effective, and the data of the internal calibration parameters of the camera is given.