Prison IoT (Internet of Things) is the application of IoT technology in prison environment. The monitoring platform is the core infrastructure in prison IoT. As more devices are integrated into prison internet to carry out some simplest tasks, the monitoring platform is required to communicate with more and more heterogeneous devices. The vast amount of devices increased the complexity in each stage of prison work flow, from deployment to operation. Prisons are experiencing more and more inconvenience and frustration as this situation become more complex. To overcome these problems, a middleware architecture is developed to help integrate heterogeneous surveillance devices from different vendors. As a result, prisons only focus on device function, thus help build more robust upper-level applications. The Java based on Intel Atom hardware implementation shows that devices can be easily introduced and managed, thus can improve prison work flow significantly.