In this paper, the time evolution of Tavis-Cummings model and the non-classical properties of field are studied The function of second order coherence is accurately evaluated and the relation between second order coherence function and atomics coupling is discussed The quantum entanglement produced in this system is studied in detail. The three-qubit entangled state can be obtained under the proper initial state. Using the Coffinan definition of three-paiticle entanglement, the entanglement measure of three-qubit is discussed in this system. The system will evolve into W-entangled state for some initiai conditions and the necessary condition for W-entangled state is given. The 3-tangle of the system will change with the system initial state, coupling coefficients between the two atoms and field or atoms.