Abstract: In view of problem of higher electricity consumption of air compressor, the paper proposed an optimal control scheme of air compressor unit, namely building dispatching model of air compressor unit to realize goal of constant-pressure and energy-saving. Optimal control principle of the model is as follows: when pipe network pressure changes, making constant-pressure decision, energy-saving decision and distribution decision for situation of each air compressor in air compressor unit to maintain network pressure in 0.58-0.65 MPa. The test result validated feasibility of the model.