A novel way to drive the double acousto-optic(AO) Q-switch in a pulse Nd:YAG laser was reported.AO Q-switch driver with 120 W output power was halved by a power distributor,and two branches were used to drive the double orthogonal AO-switches.The influence of the different opening time of two AO-switch on the laser pulse output was researched,the result indicate that synchronism of two AO Q-switch has much influence on the output of the laser pulse,When the difference of start times of two AO switches exceeds 5 ns,the laser wont be shut off effectively.If the difference is more than 18 ns,the pulse energy of laser output will drop about 20 %.