Abstract: Based on a geometrical model of metro vehicle pantograph with lower bow height, and taking the constant static contact pressure of pantograph within the working height as target, a torque function of pantograph is built by using matrix method to calculate the bow-lifting torque, according to the pantograph equilibrium equation under constant static contact pressure. Then, through in-depth research on the operating mechanism of the bow-lifting device, which is simplified and a corresponding calculation model is established. Finally, a cam algorithm available for the calculation of pantograph wire guide plate profile with lower bow height is put forward. The calculation program is composed by MATLAB software and is verified by test results.