Considering the influence of wave period on the motion of ship, the hydrodynamic model of the floating crane-lifting objects coupling system is built. This model can calculate the motion response of floating crane and lifting object under wave conditions with different wave heights and periods. And it takes stability and sea-keeping of ship, personnel comfort as well as safety of equipment into full account. By comparing swing amplitude and acceleration amplitude of the floating crane and the lifting object, the limit working condition including both wave height and period for hoisting operation of the floating crane is determined. The method for limitation operation condition analysis of the floating crane not only offers calculating foundation for the construction operating adaptability of the engineering ship and the allowable working time window of the construction sea area, but also provides a new technical approach to the arrangement for the construction plan.