The invention discloses a portable multifunctional measuring device for tunnel blasting hole parameters, and an application method thereof. The portable multifunctional measuring device comprises a depth measuring part, wherein the depth measuring part comprises a main ruler, a multi-stage telescopic auxiliary ruler is sleeved in the tail end of the main ruler, the head end of the main ruler is connected with a measuring tape, the head end of the main ruler is further connected with an angle measuring part by means of a connecting member, the angle measuring part comprises an angle measuring instrument, and the middle part of the angle measuring instrument is connected with a counter weight by means of a counter weight wire. The portable multifunctional measuring device solves the problems of requiring a large number of measurement instruments and a large number of measurement personnel in the previous blast hole geometric parameter measurement, can measure the blast hole geometric parameters by one person, is convenient and efficient, can be retracted freely, is convenient for carrying, can be used in multiple ways, can measure three kinds of parameters of the blast hole in one step, can measure the depth parameters of the blast hole through cooperation of the main ruler and the auxiliary ruler, can measure the distance between the blast holes by using the measuring tape, and can obtain an inclined angle of the blast holes through cooperation of the counter weight and the angle measuring instrument.