The entanglement dynamics of two entangled two-level atoms interacting with a coherent light field is investigated by means of the standard of entanglement concurrence. The influences of the coupling coefficient of Stark effect on the entanglement dynamics of the system are discussed. The calculating results show that the time evolution of two-atom entanglement is influenced by the coupling coefficient of Stark effect. The time evolution of two-atom entanglement displays periodic entanglement and disentanglement when the coupling coefficient of Stark effect is much smaller, while the disentanglement will disappear when the coupling coefficient of Stark effect is much larger. That is to say, the statement of entanglement can be preserved preferably.