Fuel pump assembly, fuel system and excavator

The utility model relates to the technical field of operation machinery, and provides a fuel pump assembly, a fuel system and an excavator. The fuel pump assembly comprises a fuel pump body, a first-stage oil-water separator and a second-stage oil-water separator. A low-pressure pump and a high-pressure pump are arranged in the fuel pump body, and an oil outlet of the low-pressure pump is communicated with an oil inlet of the high-pressure pump through a middle cavity. The first-stage oil-water separator is arranged at the front end of the outer portion of an oil inlet of the fuel pump body. And the secondary oil-water separator is arranged in the middle cavity. And the secondary oil-water separator is used for separating fuel oil, gas and water in the middle cavity. Through the structural arrangement, in the actual working process, fuel oil is firstly subjected to oil-water separation before being input into the fuel oil pump body, and then is subjected to oil-gas-water separation after entering the fuel oil