Disclosed are a D2D data transmission method and device. The method comprises: determining, by a D2D data sending end, a state of each sending opportunity in a sending window in the same manner as a D2D data receiving end, wherein the sending window is uniformly divided into a plurality of sending opportunities, and the state of each sending opportunity comprises a data sending state and a silent state; and sending D2D data to the D2D data receiving end in the sending opportunity of each data sending state in the sending window. By means of the technical solution provided in the embodiments of the present application, a D2D data sending end sends data on different resources (sending opportunities) or becomes silent, so that different D2D data sending ends are staggered on the resources, thereby alleviating the influence of “near-far” effects.