The invention relates to a quantitative truck loading system. The quantitative truck loading system comprises a finished product oil tank and an oil tank truck and also comprises a truck loading control computer, wherein a control unit I, an integrated circuit (IC) card reader and a receipt printer are connected on the truck loading control computer respectively; a control unit II, an regulating unit, a control unit III, a mass flowmeter unit and a loading arm are arranged between the finished product oil tank and the oil tank truck sequentially; the control unit I is connected with the control unit II and the control unit III separately; the oil tank truck is connected with an electrostatic grounding device; the control unit I is connected with the electrostatic grounding device; the regulating unit consists of two regulating valves which are connected in parallel; the mass flowmeter unit consists of two mass flowmeters which are connected in parallel; a bypass is arranged on a pipeline between the regulating unit and the control unit III; and a moveable calibration flowmeter is arranged on the bypass. The quantitative truck loading system can realize automated quantitative truck loading, and also can guaranteed metering accuracy and stability and improve the work efficiency.