According to the existing dust pollution and serious core (sample) loss in air drilling operation in open pit mine, productive experiment was carried out with air DTH hammer reverse circulation drilling technology in Lala copper opencast mine of Sichuan to test the penetration rates, the effects of dust control and core (sample) recovery percentage. The experiment was performed on 3 bore holes with total drilling depth of 483m, average drilling efficiency 8.83m/h and the whole length of core (sample) 252.43m. The effect of reverse circulation drilling was good and different drilling assembly had no influence on the effect of reverse circulation drilling. There was no dust dispersion in the test site.