In order to gain the lifting posture parameters of optomechanical module of amplifier real-timely, we research a method used to calculate the field installation lift attitude of optomechanical module by inputting the load mass and lifting height simultaneously based on existing optomechanical module field installation device. The structural mechanics model based on structure information of existing lift device and load information is simplified reasonably and established to calculate the lifting posture parameters of optomechanical module in the method. In the following, solution formula including two parameters namely load mass and lift height is derived under condition of matrix displacement method adopted. The validity of the calculation formula of the amplifier optical module lifting posture is verified through the software simulation and the attitude testing of the lifting platform of optomechanical module of amplifier with laser tracker.