Abstract: Tamping frequency is a critical parameter for railway maintenance machinery, which influences the dynamic interaction and maintenance effort of tamping operation. A dynamic impact force sensor was developed based on piezoelectric effect, which could adapt to the complex and harsh tamping environment. The high-accuracy and real-time test method for impact force on tamper was self-designed. On this basis, the influence of tamping frequency on the impact force on tamper and mechanical qualities of ballast bed was analyzed experimentally. Furthermore, the tamping machine-ballasted track model was constructed using the coupling of discrete element method and multi flexible body dynamics. The influence of tamping frequency on the contact force and motion behavior of ballasts was studied numerically. The results show that when the tamping frequency increases in a certain range, the impact force on tamper decreases and the mechanical qualities of ballast bed are improved significantly. Moreover, when the tamping frequency is 30 Hz~40 Hz, the contact force on ballasts is small and the movement of ballasts is the most beneficial; thus, the ballasts are hardly degraded with the best maintenance effort of tamping operation.