Fans "Axial Fan" defined total pressure p, static and dynamic pressure Pst P2d, not only have a clear physical meaning; but also to carry out performance tests, expressed in accordance with the fan performance parameters. In the basic performance test of the blower, the speed is usually used as a fixed value, and then create a function of flow rate variation with total pressure, shaft power and efficiency. Fan performance curve refers to the speed and density of the fluid, the fan blade mounting angle of a certain total pressure, shaft power and efficiency with a flow rate change curve. Performance curve fan following five: ① versus total pressure and flow, with the p-QV representation; curve ② shaft power and flow, with the P-QV representation; ③ versus total pressure efficiency and flow, with η-QV representation.