Abstract: As a kind of green inorganic fiber material, basalt fiber has been proved to possess excellent sound-absorbing performance for its porous structure. To explore the sound insulation effect of basalt fiber felt, basalt fiber felt and ordinary cotton fiber felt are wrapped in the same inverter compressor in this research, the noise of basalt fiber felt is tested and analyzed under various working conditions and different operation frequencies. Results reveal that under same outdoor working condition, the noise of inverter compressor increases with the increase of its operation frequency. Moreover, the noise values increase slightly with the increase of the outdoor side dry bulb temperature at all three operation frequencies corresponding to 45 Hz in the low frequency band, 65 Hz in the middle frequency band and 85 Hz in the high frequency band inverter compressor. The sound insulation effect of basalt fiber felt and cotton fiber felt in the high frequency band of inverter compressor is better than that in the low frequency band. Especially, basalt fiber felt has better noise reduction effect than ordinary cotton fiber soundproof felt at the same operation frequency, and the sound insulation effect is also better when the outdoor side dry bulb temperature is low. This study can provide a reference for the application of basalt fiber in reducing noise pollution.