To compensate the axis errors between rotation axis and vertical axis when a digital zenith camera was used in celestial positioning, a incline angle compensation method for the digital zenith camera was proposed. On the principle of incline angle compensation, the scale coefficients and the cross angle of two axes were taken into account to modify the inclinometer values. Then, a calibration method was proposed for the parameters of the two-axis inclinometer. The influence of rotation angle on calibration parameters was analyzed, and some experimental data were used to verify the calibration method. The result demonstrates that the rotation angle directly affects the calibration of CCD installation angle. Moreover, the introduction of inclinometer parameters improves the positioning accuracy. If the error of rotation angle is below 2°, the influence caused by inclinometer parameters can be ignored.