The monitoring scheme of diesel engine on offshore platform was developed,through five years of continuous monitoring and failure analysis to diesel engine on offshore platform,potential fault of used oil and diesel engine was found in nearly 30% of the monitoring samples.Most common failure characteristic of diesel engine were found,including the oil clean ability decreasing,water contamination,diesel engine bearing fault abnormal abrasion.Combined with the equipment operation maintenance on the field,integrated treatment measures were put forward,including the changing oil correctly,improving diesel waterproof and dustproof seal and shortening monitoring frequency for abnormal engines.