The embodiments of the invention disclose a method and a device for controlling data traffic. The method comprises: a data terminal sends a data request to a VPN (Virtual Private Network) server via a VPN channel, wherein the data request comprises an instruction of compressing a data resource corresponding to the data request according to a first compression rate; and the data terminal receives the data resource sent by the VPN server via the VPN channel, wherein the data resource is compressed by the VPN server according to the first compression rate. The size of the compressed data resource is generally reduced, and the user experience is not influenced after the data resource is decompressed and displayed on a smart phone, so the method solves the technical problem that the user experience is influenced by removing an important part from a web page in the method of controlling the data traffic consumed by the data terminal in the prior art.