The invention discloses a plate assembly contact point measurement method for a plate heat exchanger. The method includes the steps: coating red lead paint on the grooved top of the plate heat exchanger, wherein the red lead paint cannot flow on the surfaces of plates when the plates are arranged vertically; coating the red lead paint on one side of each plate and guaranteeing the other side of each plate to be free of paint contamination; assembling the plates of the plate heat exchanger according to set technological parameters, then unbolting bolts to observe contact points on grooves of the plates, respectively estimating red lead loss areas of original red lead coated plates and red lead areas obtained before contact by means of premade contact point profiling holes and profiling circles, calculating contact areas, and completing measurement of the contact points and the contact areas. The plate assembly contact point measurement method for the plate heat exchanger solves the technical problem of assembly quality of the plate heat exchangers.