The invention discloses a guide plate fastening structure for a plunger pump, which comprises guide plates and a cross head installed in a frame and is characterized in that the guide plate fastening structure comprises an intermediate guide plate fastening body and two lateral side guide plate fastening bodies. The intermediate guide plate fastening body comprises Y-shaped left rotating nuts and Y-shaped right rotating nuts which are respectively arranged at the upper end and the lower end of a left rotating screw and a right rotating screw. Y edge ends of the Y-shaped left rotating nut and the Y-shaped right rotating nut serve as a jacking seat respectively. An installation seat with an oblique angle is respectively installed at the upper end and the lower end of each lateral side guide plate fastening body. A telescopic adjustable jack screw is sleeved on each installation seat. a section of arc guide plate is formed by contact connection between four jacking screws and four jacking seats of the Y-shaped left rotating nut and the Y-shaped right rotating nut respectively. The guide plate fastening structure for the plunger pump is simple in structure, convenient to adjust, install and dismount, safe and reliable and long in service life.