The invention provides a space detection node detection system and relates to the space detection technology field. The system comprises one or more floating nodes and an underwater sound channel axis communication device, wherein the one or more floating nodes float on the water surface and are in communication connection according to a preset network topological structure, each floating node can freely move in a preset movement region of the water surface, the preset movement regions of any two floating nodes are partially superposed or have no superposed parts, the underwater sound channel axis communication device is arranged underwater and is used for realizing communication connection of an underwater communication target with the one or more floating nodes, the underwater communication target moves in at least one mode as follows, a, movement according to preset movement locus is realized, and b, movement is controlled by a control instruction. Technical problems of relatively poor concealment and relatively poor precision existing in a traditional underwater communication device are alleviated.