To improve the software reliability of the host computer subsystem in a simulation experimental system, a system-level House of Software Reliability (HOSR) was established. The Run-time Infrastructure(RTI) management module was taken as an example, the dependence of failure modes on the failure causes was analyzed and the relationships between the failure modes and the failure causes were disscussed. The Failure Mode and Effects Analysis (FMEA) and Quality Function Deployment (QFD) were introduced. And then, the HOSR formed by FMEA with the system concept house from the QFD was described. According to the software level diagram of the host computer subsystem, the established library of failure modes and failure causes was used to fill HOSR. Finally, the failure of RTI management module was analyzed on the HOSR analysis matrix. The analytical results indicate that, in RTI management module, there are 23 potential failure modes, 35 potential causes of failure, 116 relationships between failure modes and failure causes, 9 relationships between the failure modes, 14 relationships between the failure causes. analysis method can distinguish failure modes and failure causes much more comprehensive, especially for common-mode failures and common-cause failures. Meanwhile, it can significantly reduce the defect omission of brainstorming and staff workloads.