The invention relates to a reciprocating plunger pump which comprises a stuffing box assembly. The stuffing box assembly comprises a stuffing box body provided with an internal cavity and is characterized in that a synchronous exchange system is arranged under the stuffing box body and comprises an exchange tank (9) full of lubricating oil in the inside, and the exchange tank (9) is communicated with the internal cavity of the stuffing box body. In addition, the exchange tank (9) is communicated with a liquid inlet pipe network of the plunger pump through a one-way valve (10), and the working pressure of the one-way valve (10) is larger than the inlet pressure of the reciprocating plunger pump. Compared with the prior art, the reciprocating plunger pump has the advantages that the synchronous exchange system is arranged under the stuffing box body, it can be ensured that a plunger filler and other parts inside the stuffing box assembly always work in lubricating oil, the service life is prolonged, and friction power consumption is reduced.