A new way of the Gulf tidal energy development has been proposed to use the dynamic water-head inside and outside the Gulf for tidal power generation. Tide inconsistency will happen when it reaches the bottom of the Gulf and outside the Gulf, leading to delay of the tide on the Gulf bottom. A dynamic water-level difference is thus forming between inside and outside the Gulf, which can be used as tidal power water-head. An ideal tidal energy gulf is built up for the hydrodynamic numerical simulation. Results show that the new tidal energy development method is feasible. It greatly improves the efficiency of tidal energy compared with traditional tidal power generation way. The new idea is first proposed in the world on tidal energy, which would bring substantial changes to the traditional way on tidal energy power generation.