Survivability is defined as the capability of a system to fulfill its mission, in a timely manner, in the presence of attacks, or accidents. A key characteristic of survivable systems is their capability to deliver essential services in the face of attack, failure, or accident. Thus, it is important to deliver essential services in the survivability network system. Mobile Agent has a character of motion besides reactive, autonomy and oriented-objective as a new technology. By discussing the characters of survivability network system and mobile agent, this paper presents a model for essential services mobility based on mobile agent-MESMMA. This paper mainly focuses on the design of both MESMMA system and mobile agent inner architecture.