It was experimentally studied the improvements of the passive Q-switch short-cavity laser diode(LD) pumping laser near field through limiting the gain aperture. The LD pumping laser that have high stability, accurate Gauss near field distribution and smooth time output pulse is developed. The laser device is the key unit to attain the miniaturized laser range finder, adoptting some techniques of novel LD pumping, gain switching, short cavity, Q-switch passively, and bonding crystal to improve the beam quality using limiting transverse mode by the gain aperture; to ensure beam output of single longitudinal mode using short cavity and passive Q-switch; to abate Q-switch time shake using gain switch. The experimental results proved the method of improving the passive Q-switch short-cavity laser near field using limiting the gain aperture is usefull.