The collapses and revivals of atom population are investigated in the two-mode two pho- ton Jaynes-Cummings model, in which Stark shift with a Rotating-Ware Approximation (RWA) and without RWA are all considered. The va1ue of b (b2 = β1/β2, β1 and β2 are the two Stark shift coefficients) thects the perodic time of the collapses and revivals of atom population. Only when b=1, the periodic time is the shortest. Without RWA, we found the atom population exhibits Chaos, which is thected by Stark shift. If β1 equal to β2, the chaos is the weakest. When b deviates from 1, the chaos become stronger.