A method for identifying the presence of a man-in-the-middle is disclosed, the method is used to solve the problem that a web client can not identify whether there is a man-in-the-middle between the web client and a server, thus the transmitted information may be subject to potential security threats. The method includes: obtaining the related information of the first certificate of the server received by the web client during the handshake process between the web client and the server, and the related information of the second certificate of the server received by the web client during the non handshake process between the web client and the server (21); determining whether the related information of the first certificate and the related information of the second certificate are matched (22). A device for identifying the presence of a man-in-the-middle is also disclosed.