By using the dispersion pulse propagation theory and the refractive index of air Ciddor equation, the cross-correlation function of the femtosecond pulse laser was derived. According to the theory that the resulting expression of the cross-correlation function depends on the spectral distribution of the laser source, the numerical model of the cross-correlation patterns among pulses of the femtosecond pulse sequence propagating in air with different spectral distribution under different optical path difference and the change of environmental parameters was created. Results show that, the cross-correlation pattern has a stable chirp and linear broadening with the increase of propagation distance, but the change of the environmental parameters give rise to the shift of the correlations patterns without any extra linear broadening or chirp.