The invention provides a rut preventing device and method for the long uphill section of an asphalt pavement. The rut preventing device comprises a central control unit, a pavement temperature acquiring system, an automatic spraying system and a running safety warning system, wherein the central control unit analyzes and judges the received real-time temperature data and the received real-time traffic information, and controls the automatic spraying system and the running safety warning system to work; besides, the central control unit transmits the working state of the systems to a server in a remote manner through a 3G wireless transmission module; besides, the central control unit receives commands from the server. The rut preventing method disclosed by the invention is simple, rapid and highly efficient, and is low in cost; both of running safety and pavement maintenance are taken into consideration; the temperature of the asphalt pavement can be effectively lowered, so that the generation of ruts on the asphalt pavement can be effectively relieved, and the running safety and running comfort on the asphalt pavement under high-temperature conditions in summer are improved.