Conditions of diesel generators on an offshore drilling platform are crucial for oil production, if diesel generators can not work, the efficiency of oil production will be reduced, even worse, it will be a crisis to the offshore drilling platform security. So it is important to reduce maintenance costs and prevent major failures of diesel generators by using some effective means, such as establishing effective monitoring methods and strategies, predicting diesel generators’ working status and managing their operation data, it also can improve convenience for Platform crews’ operation and maintenance. Some on-line or off-line monitoring methods for diesel generators are applied widely, however monitoring strategies and integration technologies for the platform are not yet available. An integration strategy of online and off-line monitoring was proposed by using the instantaneous speed method, CP method and thermal parameters method. A suitable performance monitoring system for diesel generators is composed of performance monitoring module, data management module and network communication module. The system was developed based on virtual instrument technology, by data acquisition, analysis, processing of different types of sensors and design of monitoring strategy and system interface, the status monitoring and prediction of diesel generators is realized. The method was tested on a laboratory diesel engine, the performance and function of the monitoring system were verified. Then the system is validated on a drilling platform, and results indicated that the functions of the developed system met the designed requirements and the performance was reliable.