In order to strengthen the accuracy and stability of the measurement information, and to enhance the safe and stable operation of the new generation intelligent substation and smart grid, it studied the metering abnormal diagnosis technology, put forward the design scheme of the metering abnormal and online diagnosis system of the new generation intelligent substation, realized real-time processing of the metering abnormal and online diagnosis analysis of the abnormal reason. The analysis model for experiment was set up. The results and tests show that the metering abnormal and online diagnosis system of the new generation intelligent substation can make the real-time analysis and review, and real-time monitor the working condition of the metering system for the whole substation. The design and implementation of the system provides a good platform for realizing the reliability, stability, versatility and interconnection of the metering system of the intelligent substation. It is suitable to the construction of the new generation intelligent substation.