The invention discloses a multi-unit composite spiral plate type heat exchanger and belongs to the technical field of heat exchange equipment. The heat exchanger is designed for overcoming the defectthat an existing spiral plate type heat exchanger cannot overcome the defects of flow way blockage and difficult deep cleaning. The multi-unit composite spiral plate type heat exchanger comprises multiple heat exchange units, wherein each heat exchange unit is provided with a metal plate with a spiral groove, an upper cover plate, a lower cover plate, a first side plate with a first fluid port anda second side plate with a second fluid port. The heat exchange units are divided by metal plates into upper flow ways and lower flow ways. The metal plates, the upper cover plate, the lower cover plate and the side plates are fixedly connected through fasteners. The heat exchange units are perpendicularly stacked and share the adjacent cover plate, the heat exchange units are arranged in a composite mode, fluid in the flow ways of the heat exchange units is arranged in the mode of cold-hot-hot-cold mode. The characteristics of a plate type heat exchanger and a spiral plate type heat exchanger are combined, the structure is compact, the heat exchange efficiency is high, modular extension is convenient, and the multi-unit composite spiral plate type heat exchanger has the advantages of being easy to machine and easy to detach and clean.