Abstract: AGFT（Autornatic Generation of Fault Trees） is the problem with which system reliability analysts are much concerned. This paper introduces a development environment of AGFT expert system TEE. As a tool for developing AGFT expert sysem, TEE can be used to develop AGFT expert system not only for AGFT of ordinary complex systems, but also for AGFT of the complex systems that include complex control loops. TEE’s structure, the knowledge base organizatin and the knowledge representation, and the inference algorithm are also discussed.