Abstract: The dust and harmful gas concentrations of underground crushing chamber and transportation seriously pollute the environment,affecting the health of underground workers and restricting the safe and efficient production,which is a technical problem for enterprises to solve.Through analysis of underground air pollutant concentrations and sources,the countermeasures including source control,pollutant spreading control,ventilation system renovation and individual protection enhancement are determined.The results show that the dust concentration decreases by 74.5 % and 68.2 % respectively,and the harmful gas CO concentration decreases by 43.7 % and 50.2 % respectively,NO2 concentration decreases by 63.3 % and 59.6 % respectively，oxygen volume fraction increases by 4.6 % and 5.7 % respectively in the crushing chamber and transportation ramps.The working environment has improved obviously and the safe operation in mines is ensured.