The invention relates to a method for calculating a rock mass integrity coefficient Kv during tunnel construction. The method comprises the following step of: drawing a rock mass hole depth-wave velocity curve graph according to a rock indoor test and a rock mass longitudinal wave velocity test result at a tunnel construction site, and further rapidly calculating rock mass integrity coefficients Kv of different hole depths in a tunnel construction stage. Accord to the method, the rock mass integrity coefficients can be rapidly obtained in the tunnel construction stage, the longitudinal wave velocity of the rock mass at a tunnel face is tested by using a single-hole test method with an acoustic emission instrument, the longitudinal wave velocity vp of the rock mass is rapidly tested by using a drill hole of tunnel face construction, the longitudinal wave velocity vr of the rock mass is tested by combining a core drilling rock sample to carry out an indoor test, and the integrity coefficient of the rock mass is quantitatively calculated in the construction stage. The method starts from the definition of rock mass integrity coefficients to make a method of evaluating the integrity ofa surrounding rock in a tunnel construction stage be supplemented and perfected.