The embodiment of the invention provides a traffic flow assisted wireless data transmission method and device, applied to the technical field of communication. The method comprises the following steps: for a base station side, an idle base station receives a first mobile service data request sent by a hotspot base station in an idle cell; the idle base station obtains road traffic condition information, and determines the data volume transmitted from a vehicular terminal to a user terminal according to the road traffic condition information; the idle base station sends mobile service data to the vehicular terminal according to the first mobile service data request and the data volume; for the vehicular terminal side, the vehicular terminal receives the mobile service data sent by the idle base station in the idle cell; when a vehicle is in a parking state, the vehicular terminal transmits the mobile service data to the user terminal in a hotspot cell; for the user terminal side, the user terminal sends the mobile service data request to the hotspot base station in the hotspot cell; and the user terminal receives the mobile service data sent by the vehicular terminal.