Objective Analysis the S135 drill pipe’s corrosion holes Methods. In this paper, the chemical composition analysis, macroetching, metallographic test, mechanics performance testing, and scanning electron microscopy(SEM) analysis of the S135 drill pipe material,include mechanical property 、chemical composition 、metallurgical structure 、non-metallic inclusion 、and grain size ，and drill pipe’s top circle surface,and corrosion holes’s characteristics and corrosion products were analyzed. Results The drill pipe’s chemical composition、. mechanical property、metallurgical structure、grain size and non-metallic inclusion are qualified. Conclusion The analysis results show that the hole of the S135 drill pipe is caused by the stress corrosion fatigue. Its three factors: first, outer circumference surface of the existing pits,pockmarks; second, drill pipe under alternating bending stress; third, the pipe round face local oxygen corrosion.