The fluorescence photon correlation in a three-level Λ-type atom in a broadband squeezed vacuum is investigated. By using the equation for the reduced density operator and the quantum regression theorem, the dynamics of the intensity correlation and the evolution are numerically calculated. The results show that the behavior of the photon correlation can obviously be modified by the squeezed vacuum. When the coherent field is so weak that the atomic coherence is negligible, the anticorrelation is preserved and the time for evolving into normal case is reduced via squeezed vacuum, and the populations of different levels are changed. However, when a stronger coupling field is applied, the combination of atomic coherence and squeezed vacuum leads to the changing from strong photon correlation to normal photon correlation, attributing to that the coherent population trapping is spoiled by the squeezed vacuum.