Abstract: A marine diesel engine was discovered that different tone came out of the booster. After the demolition, the damaged valve residual materials was found in the catching on the nozzle ring. And the booster was broken by intake valve disc off the block. By means of macroscopic examination, chemical composition analysis, mechanical property testing, metallographic examination and hardness testing, the failure reasons of the value were analyzed. The results showed that the failure of valve was caused by hot-corrosion fatigue of high-temperature oxidation. Finally, some suggestions for current valve technology were proposed.