To solve the problem of Angle fine-tuning in the vertical direction of optical devices, we propose an Angle fine-tuning mechanism based on Bridge-type Mechanism. In this paper, we use the method of compliance matrix to establish the statics model of the mechanism and calculate the influence of each parameter on the magnification of the model, then verify it by finite element simulation. Meanwhile, we deduce the calculation formula of compensation value by simulation value and theoretical value to establish Theoretical equations of motion for this mechanism. The results indicate that the simulation results agree well with the theoretical calculation results, after introducing the compensation value, the error caused by the amplification loss of the mechanism can be compensated well to ensure the accuracy of the derived formula. © Published under licence by IOP Publishing Ltd.