The invention discloses a light five-cylinder plunger pump. The light five-cylinder plunger pump comprises a power end assembly and a hydraulic end assembly, wherein the power end assembly is connected with the hydraulic end assembly; the cylinder spacing of the light five-cylinder plunger pump is 9in; the power end assembly comprises a crank shaft, the crank shaft comprises six crank necks and five crank throws, the crank necks and the crank throws are fixedly connected, the distance between rotating centers of the crank necks and the crank throws is 101.6 mm, and the stroke distance of the light five-cylinder plunger pump is 203.2 mm. According to the light five-cylinder plunger pump, power is increased by increasing stroke, reducing transmission ratio and improving bearing capacity, andmeanwhile, dead weight is reduced by reducing the cylinder spacing, the tooth number of a big gear and the tooth thickness of the big gear and a pinion. The light five-cylinder plunger pump meets conditions of working in the area with severe well cementing operation conditions in aspects of weight and power simultaneously, and working efficiency is increased.