High performance simulation has great prospect of application in the fields of Materials Science and Engineering. In high performance simulation, high performance computers are used to improve the performance of simulation. As one of the simulation standards, HLA simulation was greatly applied in computer simulation. In HLA simulation domain, many RTIs are designed to support the simulation in LAN/WAN environment. Because of the general TCP/UDP communication mechanism, high simulation performance can’t be achieved by these software on high performance computer. To improve the simulation performance, a customized RTI software for high performance computer and PC hybrid environment is designed. By using of partially hierarchical design on functional distributed architecture, large scale simulation can be supported. An adaptive communication mechanism is proposed, which can adapt communication between different RTI components to shared memory, Infiniband and Ethernet automatically, thus can greatly improve communication performance. In addition, this paper explains the related design in this customized RTI.