The utility model provides a light -gas gun is shell for downhole explosion, including semi - cylindrical's first casing and second casing, the corresponding connect buckle, first casing and the mutual lock of second casing of being provided with on first casing and the second casing to connecting through the buckle and fixing in order to form both ends confined tubular structure, the junction offirst casing and second casing still is provided with the sealing strip, and the junction of first casing and second casing upper end is still seted up leaded hole and is led air pipe hole. It has thecomplexity operation of water cannon hole, storage space stringency to aim at solving, and reduce by a wide margin that explosive blasting back produces raise soil, toxic gas scheduling problem in alarge number. The utility model belongs to the technical field of the blasting.