The nonadiabatic photodissociation dynamics of the (A) over tilde -Slate ammonia (NH3) was Investigated using I four-dimensional wave packet model. The branching ratio between the excited NH2((A) over tilde (2)A(1)) and ground NH2((X) over bar B-2(1)) products was obtained its function of energy for photodissociation mediated by several low-lying vibrational states in the ground electronic state of NH3 The calculated results could not fully account for the experimental observations of strong mode specificity in nonadiabatic dynamics but agree qualitatively with a recent trajectory-based coupled-surface study using the Same potential energy surfaces Several possible sources of inaccuracy,ICY are discussed.