In the multi-processed and multi-threaded complex network environment, application system will appear the unforeseen deadlock problem. This deadlock problem may cause service interruption, and even can cause the crash of the application system. On the other hand, malicious attacks on the system and other random events will also cause serious consequences. The security defense of service operating has become another important problem in the information security field. In order to solve the above problem, this article proposes the security defense technology based on Mandatory Running Control, which can solve the unpredictable deadlock problem from the system kernel level, prevent illegal process running and restrict allowed process’s behavior, realizing security defense of service operating and ensuring the system running continuously and reliably. This paper introduces the principle, theoretical model and the technologies in the implementation of the security defense technology based on Mandatory Running Control.