With different design idea, improvement was made on matrix formula of traditional diamond bit by selecting high strength diamond and wear-resistance diamond polycrystalline and adjustment was made on the sintering parameters of traditional diamond bit. A large diameter reinforced diamond bit was developed, which has advantages over traditional diamond bit in wearing-resistance, anti-impact toughness and bit diameter retention. The bit service life in gravel and broken formations and drilling rate were improved with no changes of traditional drilling parameters.