Rotary drilling bit is applied to all kinds of soft and hard soil layer, rock and concrete layer, with conical teeth body design and has strong penetrating performance. It uses high strength steel alloy steel body which through heat treatment, and can keep high toughness and high wear resistance; the cutting head use the hard alloy which through hot isostatic pressing, and spring are made of high strength spring steel, wear-resistant washer is made by high strength wear resistant steel plate which through heat treatment.