An investigation is made on the implementation of the embedded multi-task software based on the control object model state machine behavior in IEC 61850. The significance and method of building the model for the control object state machine behavior are analyzed. By referring to the behavior criterion for substation switching operation and the demand for application of access control based on Ethernet， as well as the characteristics of multi-user visiting multi-object simultaneously in access operation， the implementation mode of the real-time and multi-task kernel of the control object state machine behavior is proposed. A method of software implementation based on operating systemμC/OS-Ⅱis described.