The invention discloses an onlinetransaction pre-test method and device, a medium and an electronic device. The method comprises the following steps of obtaining a transaction message required by a test from a test server; distributing the transaction message to a transaction file and storing the transaction message; allocating a transaction identifier to each transaction file; generating a comparison table of the user information and the transaction identifier; Receiving a test request sent by the client; Finding a transaction identifier corresponding to the user information from a comparisontable of the user information and the transaction identifier; reading a transaction message corresponding to the transaction type in the test request from a transaction file corresponding to the found transaction identifier; and sending the read transaction message to a client, so as to compare the transaction message with a pre-stored transaction message and determine whether the test is successful. According to the present invention, the technical problem that in the prior art, when a functional system of a financial institution conducts joint debugging testing, dependence on an external enterprise testing server is high, and testing is very easy to be limited, is solved.