The rotating laser-scanning system is a spatial multi-target parallel angle sensing system， which is based on a precision turntable and combined with multiple lasers. To improve the performance of the system's light source， a new type of axis structure was designed that uses optical fibers to import light sources from the outside. However， when the laser passes through the hollow rotating shaft and enters the reflector group at a certain angle， if the incident cylindrical lens is tilted， the scanning light surface pattern will change.To address this problem， a method for adjusting the attitude of the laser optical axis based on the transmissivity of parallel lines was studied. With the help of a laser tracking measurement platform， individual fittings were performed for the optical axis and the rotational axis system. A calibration method for the tilt error of the optical axis was established.The experimental results demonstrate that the spatial angle between the adjusted optical axis and the rotational axis exceeds 0.15°， fully satisfying the angular requirements for laser incidence on the cylindrical lens in terms of the central linearity of the light cross-section.This adjustment scheme is applicable to the assembly phase of the system， enabling the scanned light to approach an ideal plane more closely. This contributes to the enhancement of the system's measurement accuracy.