The invention provides a transaction processing method based on a general preposition machine. The interface format information of various initiating terminals, the interface format information of various receiving terminals, and the initiating terminal identifiers and the receiving terminal identifiers corresponding to various transactions are pre-configured in configuration information; when a transaction request message sent by an initiating terminal is received, the related configuration information is called, the transaction request message sent by the initiating terminal is converted to a message in line with the interface format of a corresponding receiving terminal, the message is sent to the corresponding receiving terminal, a transaction result message fed back by the receiving terminal is received, the related configuration information is called again, the transaction result message fed back by the receiving terminal is converted to a message in line with the interface format of a corresponding initiating terminal and the message is sent to the corresponding initiating terminal. Communication and message conversion requirements between the receiving terminals and the initiating terminals corresponding to various transaction types are met, and the preposition machine development cost can be effectively reduced.