Reciprocating pump

A reciprocating pump comprises a driving end structure and a fluid end structure; the driving end structure comprises a machine body and a reciprocating mechanism; the reciprocating mechanism comprises a connecting rod, a plunger piston and a crankshaft; a supporting bearing is arranged on the crankshaft; a connecting rod bearing is mounted between the connecting rod and a crank of the crankshaft; the connecting rod bearing is eccentric relative to the supporting bearing; an inner hole of the connecting rod is formed in the way that an upper semicircular arc, a lower semicircular arc and a middle straight-line segment are connected; the connecting rod bearing is in contact with and connected with the straight-line segment of the inner hole of the connecting rod; and a connecting rod head of the connecting rod is connected with the plunger piston. The utility model has the benefits that integrally the parts of the reciprocating pump are less; the structure is compact; the material is saved; and the occupied ar