Abstract: Serious damage occurred on offshore platform pipeline in the production only after its service for only 2 years,the leak position was found in the pipe weld connections at the bottom of the pipe.The failed pipe was analyzed by means of chemical and mechanical properties tests,microstructure examination,XRD and energy-dispersive spectroscopy (EDS) to find out the corrosion and leakage reasons.The results showed that the reason of the pipeline corrosion was CO2 corrosion.The priority leakage reasons of welding were improper welding seam and high sensitivity of groove.