Abstract: To predict the ground settlement caused by tunnel excavation more accurately, the traditional Peck empirical formula was modified by the random medium theory, and a new calculation method of ground settlement caused by tunnel excavation was proposed. The relationship between the land surface settlement characteristics and the reasonable number of units n under the conditions of different span ratio H/D and soil loss rate μ is studied, and a method to determine the reasonable number of units n is proposed. The ground settlement calculated by the modified Peck formula and the traditional Peck empirical formula is compared with the measured data. The results show that the modified Peck formula can better predict the ground settlement caused by tunnel excavation than the traditional Peck empirical formula. The research results extend the application range of traditional Peck formula and enrich the calculation method of ground settlement caused by underground excavation in tunnel construction.