With the requirement of safe navigation in South China Sea, airborne laser bathymetry technique becomes attractive in China recently. A prototype of laser airborne depth mapping (LADM-I) system was developed. System included a diode laser pumped solid-state laser with a repetition rate of 200 Hz and the peak power of 2 Mw, a 15°nadir quasi-elliptical scanner, a combination unit of DGPS and an electronics compass, and a post-flight data processor. System has been demonstrated in South China Sea during last two years. In order to improve sounding density, survey productivity, maximum penetrable depth and accuracy of depth, a new generation of LADM-II is under developed. System will be constituted of a 1 kHz diode pumped laser, INS and KGPS. The performance will also upgrade to meet the higher requirement. In this paper, the detail parameters and specifications of LADM-I, and the experimental result will be reported. The protocol of LADM-II system will be also present.