The invention discloses a positioning connection device, a positioning connection system, a building module device and a connection method. The positioning connection device comprises a top referenceelement and a bottom reference element, wherein the top reference element is connected with the top of a building module; the bottom reference element is connected with the bottom of the building module; the top reference element comprises a top reference plate and a top positioning part; the bottom reference element comprises a bottom reference plate and a bottom positioning part; through the toppositioning part and the bottom positioning part, the top reference element and the bottom reference element are mutually and independently positioned in the top prepositioning position and the bottom prepositioning position; and the top prepositioning position and the bottom prepositioning position have the identical horizontal coordinate position relative to the preset reference point and are vertically and correspondingly arranged. The positioning connection device disclosed by the invention has the characteristics that the positioning precision is high, the operation is simple, and the structure is compact; the positioning connection device can be used for reducing the influence of manufacturing errors and stacking errors on the building module positioning precision; and the fast, simple and high-precision stacking and connection requirements of the building module in project fields are met.