The conventional axis test adopted the position mode that uses a single theodolite to read the pitch absolute value. In this conventional axis test case, the line array and the axis of the detector are parallel to the +Y direction and +Z direction of the global coordinate system. The off-axis camera axis test, different from conventional axis test, did not follow the principle that the detector axis was parallel to the camera cube mirror. It is separated from the global coordinate system, the camera cube mirror coordinates and optical axis array. So a new axis test is proposed. It is need to adjust the optical axis to theory position of the camera coordinate system, and the four-colored line array should be parallel with five-colored line array before the experiment. With the aid of bracket, the camera axis was extract to camera cube mirror a and drilling cube mirror b using theodolite. Respectively, the direction cosine matrix was used to reduce error of camera axis. The accuracy and the multi-dimensional positioning of nine-band linear array were analyzed, and also the experiment image was obtained. The results show that the optical axis matrix meets the requirements and the location extraction method is reasonable and feasible.