The invention provides a data processing method and device, and relates to the technical field of internet data transmission. The data processing method comprises the steps of obtaining initial transmission data, wherein the initial transmission data are the data transmitted between a server and a client, and the initial transmission data comprise the following types, including, webpage framework data, text data, image data and audio-video data; performing coding operations on the initial transmission data and obtaining target transmission data after the coding, wherein coding operations for different types of initial transmission data are different; and transmitting the target transmission data obtained after the coding between the server and the client so as to solve the technical problem of relatively poor compression effect when the transmission data of the internet are compressed in the prior art.