Safe operation of ventilation machine played an important role in coal mining process. Shortcomings of average velocity pressure measurement method and velocity measurement method were analyzed in this paper, as well as wind measurement principles, advantages and attentions of static pressure difference method. In actual air volume measurement, the result showed that resultant errors of static pressure difference method, fast compression method and artificial wind table method were in range of standard requirements, which meant that fan air volume measured by static pressure difference method could achieve corresponding measurement requirements.