The invention provides an automobile fuel oil injection system, which comprises an oil filling pipe assembly and an oil tank assembly, wherein an oil injection opening and a ventilation opening are formed in the oil tank assembly; the oil filling pipe assembly comprises an oil filling pipe, a flow guide pipe, a transition pipe and a ventilation pipe; the back end of the oil filling pipe and the back end of the ventilation pipe are respectively connected with the oil injection opening and the ventilation opening formed in the oil tank; the flow guide part is arranged at the inner wall of the front end of the oiling pipe, and comprises a flow guide cavity and a flow guide pipe; the flow guide pip communicates with one end of the transition pipe; the other end of the transition pipe communicates with the ventilation pipe; oil liquid sequentially flows into the flow guide pipe and the transition pipe from the flow guide cavity along the oil filling pipe; two plate valves with different cross section sizes are arranged in the transition pipe; in addition, the volume of a space formed by the two plate valves is greater than the volume of a space formed by the flow guide pipe and the plate valve near the flow guide pipe, so that the resistance type attenuation effect is formed; the oil liquid can be effectively prevented from being sprayed out from the oil filling pipe; the waste of gasoline and the environment pollution is avoided; meanwhile, air in the pipe can be exhausted in time; the pressure balance inside and outside the pipe can be ensured.