With the increasing mature of hardware technology and the continuous reduction of RFID production cost, the technology has been widely used in many fields. This paper proposes a real-time event stream framework for RFID system and develops a retail supermarket management system for the purpose of commodity monitoring and tracing. An event-centric architecture for the RFID real-time is designed, which can support both real-time event queries over event streams and history event queries on event databases. Event types of retail supermarkets are analyzed in details, and the event relation diagram among them is given. Based on the framework, an event filtering method using a hash table to remove redundant data and an improved SASE method to process complex events are presented.