Abstract: Aiming at the problems that the tower crane often needs to transform arm length and the corresponding hoisting load varies frequently in the practical situation, a new parameterized calculation system of tower crane counterweight was developed, which was more practical, simple and convenient. The system which was based on the feature and working conditions, could build the tower crane main structure parametric model with Pro/E(the three dimensional design software), design and assemble automatically, according to the different length of the crane arm. It could transfer and invoke the data using VB cooperated with the Pro/E as the developing tool, so as to simplify the model and calculating process, which was proven to be correct and feasible by the examples.