Provided are an RFID operating system and an RFID system operating method for allowing multiple RFID readers to read tags without collision. The RFID system operating method includes the steps of grouping RFID readers spaced apart by more than a spacing distance capable of avoiding collision between RFID readers into a single group to determine at least one group, classifying RPM readers included in each group into at least one sub-group based on a read time of each RFID reader, and driving the RFID readers such that RPM readers belonging to at least two different sub-groups that do not collide with each other simultaneously operate. According to the present invention, switching is performed sub-group by sub-group to reduce the number of switching operations and sub-groups can simultaneously operate to decrease a read time.