The present disclosure discloses an electrical connection device and a plug assembly, the electrical connection device comprises a receptacle assembly and a plug assembly. The receptacle assembly comprises a cage and a connector. The plug assembly comprises an outer housing and a communication module provided in the outer housing. The outer housing has a main body which can be inserted into the cage along the mating direction to be mated with the connector. The receptacle assembly is provided with at least one guide groove extending along the mating direction, and the outer housing of the plug assembly is provided with at least one guide block protruding from the main body to correspond to the at least one guide groove, when the plug assembly is mated with the receptacle assembly, the at least one guide block enters into the corresponding guide groove along the mating direction.