By means of numerical methods,we studied the fidelity of the system which contained a moving two-level atom and the binomial light field.The impact of different initial states is discussed to the fidelity of quantum states.The result showed that the velocity of atom effect the oscillation period of the fidelity,and different initial state of atom and the optical field parameters on the fidelity have a bigger influence.When the atom is in superposition state and the field has a bigger initial average number of photons the fidelity of the system has a higher value.