The utility model relates to a high-pressure fuel oil pump, which comprises a high-pressure component used for receiving fuel oil from an oil tank and pressurizing the fuel oil, and a driving shaft which drives the high-pressure component by a cam, wherein the high-pressure component comprises a plunger sleeve, a plunger reciprocating back and forth in the plunger sleeve, and a check valve device which is arranged in the plunger sleeve, so a pressurizing cavity is defined between the front end of the plunger and the check valve device. An oil supply hole is formed in the plunger sleeve, and the fuel oil is absorbed into the pressurizing cavity through the oil supply hole; and a leaked oil discharge channel making the fuel oil which is leaked from the pressuring cavity along the gap between the plunger and the plunger sleeve totally return to the oil tank is also formed in the plunger sleeve, so the leaked high-temperature fuel oil is totally returned to the oil tank, the temperature of the fuel oil in the pressuring cavity can not be increased, and the viscosity of the fuel oil can not be reduced.