The invention relates to an internal and external network database access method based on an information exchange bus. The method comprises the first step that the bus analyzes the communication data entering the bus on a TCP/IP layer and analyzes a data package according to a closed form data flow protocol and a transparent network substrate protocol, the second step that a data package of the transparent network substrate protocol is processed, the third step that a data package of the closed form data flow protocol is processed, and the fourth step that the filtered safety data package are sent to an appointed database server through the bus. The internal and external network database access method based on the information exchange bus achieves safe transmission of information across the internal electric power information network and the external electric power information network, further analyzes and filters the operation access of the database, and prevents the external network from injecting attack to the database of the internal electric power information network.