This application discloses a network attack determination method, a secure network data transmission method, and a corresponding apparatus. In this application, a browser client terminal obtains attack rules formulated by a rule configuration server, and after obtaining feedback information that is returned by a network according to a webpage browsing request, determines, according to a comparison result between the attack rules and the feedback information, whether the webpage browsing request encounters a network attack, thereby resolving a problem in the prior art that a network attack cannot be identified. In addition, after determining that a network attack is encountered, the browser client terminal performs network data transmission in a secure manner, which can avoid impact from the network attack, and improve security of network data transmission.