Changeable measurement baseline and diversity of space configuration are advantages of spacecraft formation implementing deep-space exploration mission. They are closely related to the reconfiguration capability of spacecraft formation. Aimed at the issue of optimal control for Halo orbits formation reconfiguration, this study firstly analyzed the configuration characteristics of Halo orbits formation, then the Hamiltonian equation of optimal control for Halo orbits formation reconfiguration were deduced. Iterative method for solving the Hamiltonian equation was built based on the first generating function. Simulation of optimal control for Halo orbits formation reconfiguration in the Earth-Moon system was carried out, and the validity of this iterative method was verified. Simulation results show that sun perturbation has huge influence on the fuel consumption of optimal control during the process of Halo orbits formation reconfiguration, and the fuel consumption can be reduced by selecting the reconfiguration times correctly.