In view of the fan energy saving problem, this paper adopts the experiment system of the mine main fans developed by the researchers, and determines that the K45-4-№9/18.5kW axial flow fan performance parameters of main fan under frequency and power frequency is 50Hz. It uses the software analysis of experimental data and drawing fan performance curve. Results show that the main fan in the frequency conversion 100% and power frequency in both cases run is broadly in line with a fan performance curve; frequency conversion 100% air volume and air pressure curve at runtime is bigger than runtime power frequency curve fluctuations, illustrate air pressure of frequency conversion 100% is more susceptible to the influence of the air; under the condition of large air volume, it runs the power frequency relative to the frequency conversion 100% energy-saving operation, the biggest power saving rata reaches 3.756%; power frequency efficiency is higher than the efficiency of the frequency conversion 100%, and the maximum efficiency of the difference is between the value of 2.93%.