Tower cranes are made of steel structure, which account for more than half of their weights. Therefore, steel structre optimization of tower cranes is important for the development of design technology of tower cranes. This paper develops a systemic optimization method for tower cranes based on Ansys OPT, combined with finite element analysis (FEA) and stability theory. This mathod is firstly used in the optimization of the boom of luffing jib tower cranes. New optimization model of the boom of luffing jib tower cranes is introduced and the corresponding optimization program is developed. The integration of the calibrating of overall stability and single-limb stability of luffing jib tower cranes, FEA and OPT is realized by extracting some parametes from FEA results, such as weight and axial force. Rapid optimization of the boom of luffing jib tower cranes is realized by the parametrization of non-design variables. Direct reading of optimization results is realized by the discretization of design variables. Finally, the boom of a tower crane with movable arm is optimized with the optimization program to demonstrate the effectiveness and superiority of the optimization method.