In the backfill engineering of the 3206 block of the third runway of Hong Kong international airport,the discharge performance of the cutter suction dredger’s diesel engine is substandard. Based on the analysis of the 16V240ZC diesel engine of cutter suction dredger “Tianbin”,we rematch the supercharger,renovate the the cooling water system,install the variable turbocharger geometry(VTG）electronic control system,and implement the real ship application.The results show that the air-fuel ratio of the improved diesel engine is optimized,the combustion efficiency is improved,the fuel consumption is reduced by 3%,the smoke value FSN decreases from 0.61 to 0.40,and the emission performance is improved.