The invention discloses a smart grid intrusion detection system and method. The system comprises: a monitoring module used for obtaining data of electrical equipment in a smart grid; an information preprocessing module used for preprocessing the data in the electrical equipment to generate grid information data; a data association module used for performing integration and fusion on the grid information data to form fusion data; and a depth detection module used for analyzing the fusion data of the smart grid to identify the type of an intrusion attack. By adoption of the smart grid intrusiondetection system and method provided by the invention, the operation data in an information system can be comprehensively obtained to effectively identify malicious attack behaviors, the scalability of intrusion detection is improved while the intrusion detection precision of the smart grid is improved, and the false alarm rate and the missing report rate of the intrusion attack of the smart gridare reduced.