The basic operating principle and process,different ignition manner and three natural parameters(gas inhomogeneity,absorbance(water),flame emission) of Laser-induced Spark Ignition in the Natural Gas Engine were introduced in this paper.A comparison of some parameters of combustion and exhaust emission such as burn duration,misfire knock limit,NO_xemission etc between Laser-induced Spark and conventional spark plug ignition had been carried.The merits and demerits of Laser-induced Spark Ignition,application prospect of Laser-induced Spark Ignition in the Natural Gas Engine were pointed out.