The three-qubit entangled state in Tavis-Cummings model for two identically steady two-level atoms interacting with single mode field can be generated when the atom-field interaction is far from atom-atom interaction.By analyzing three-qubit entanglement of the system,we obtain that the entanglement of the system will change with the variation of system initial state,coupling coefficients between atom and field or atoms.Especially,when the initial state is special,the system will stay in W-entangled state.The necessary condition for generating W-state is that the coupling constant between two atoms is more less than that of between an atom and field.