We consider a Geom/G/1 gate service system with multiple adaptive vacation based on the classical Geom/G/1 queueing system. By using regeneration cycle approach, we obtain the PGF (Probability Generating Function) of the stationary queue length. Because of the independent property of the waiting time and the arrival process after its arrival, the PGF of the stationary waiting time is derived. Finally we obtain the average probabilities of various system state, some special cases are given to show the new model’s general properties.