The invention discloses a traffic safety control method and system based on DPI and cloud synchronization. The method comprises the following steps: using DPI technology to perform depth analysis on each packet that flows through a router, distinguishing malicious traffic and normal traffic, intercepting the malicious traffic, jumping a user to a prompt interface, and reminding the user that web pages to be accessed are harmful; and if the malicious traffic is the severe malicious traffic, then directly performing an interception operation, and prohibiting the severe malicious traffic to communicate with a client. The traffic safety control method based on the DPI and the cloud synchronization provided by the invention fully considers the diversity of security threats and the continuous development of private information stealing means, stores malicious links in the way of cloud storage, and updates a malicious linked database regularly; and meanwhile, the method also considers the present situation that the user is very lack of information security knowledge, and transfers the responsibility of the user privacy protection from the user itself to a public WiFi system, so as to realize the private information protection of the user technically.