RFID is an emerging technology which brings enormous productivity benefits in applications where objects have to be identified automatically. RFID Middleware is a new breed of software system which facilitates data communication between automatic identification equipments like RFID readers and enterprise applications. It provides a distributed environment to process the data coming from tags, filter and then deliver it to a variety of backend applications via various communication protocols including web services. Load balancing is an important factor to provide a more steady and flexible working environment for RFID Middleware. In this paper, we propose load balancing method using Connection Pool in RFID Middleware system. Our proposed Connection Pool is composed of four components. They are CPT (Connection Pool Table), CPM (Connection Pool Manager), MMT (Middleware Manager Table), ICC (Interrupt Check Component). We also present architecture and detailed design for Connection Pool. Our proposed Connection Pool provides a decentralized and steady data processing for RFID to load balancing, which can enhance system flexibility and availability.