An experimental airborne laser bathymeter has been developed and a filed trial has been conducted. The Q-switched and frequency-doubled Nd:YAG laser output is of 100 Hz pulse repetition rate, 2 MW peak power, and 8 ns pulse width. The green light receiving telescope is transmissive with a 1400 mm focal length and 200 mm aperture. The varying-gain control of the PMT and logarithmic amplifier are used to compress the 105 dynamic range of received signals. The system was installed in a helicopter. The experimental results are described in the paper.