In order to research the displacement air conditioning in cinem conditioning system with wall diffuser in cinema with the CFD. According a, the writer simulates the displacement air to the result of the computing, we can find that if we adjust the position of the openings and parameter of air-inlet in reason. It is useful to make good use of displacement air conditioning system with wall diffuser and extend the saving energy methods by using the CFD technology in designing the air condition system in cinema.