Abstract: Considering inadequacy of the traditional force models for commonly used constant-section disc cutters in engineering, a study was conducted to establish the rock-breaking force law for constant-section disc cutters to guide the design and construction of practical engineering projects. In this study, a three-dimensional rotational cutting model of disc cutters for rock breaking was developed using the finite element method to effectively simulate the rock-breaking process. By calculation, the cutting force of the constant-section disc cutter during rock breaking was obtained and compared with experimental and literature data. The results indicated a good agreement between the cutting force of the disc cutter and the actual situation, validating the reliability of the simulation. Rock-breaking excavation tests show that the measured normal force of the cutters varied with time, with fluctuating characteristics, which was consistent with the simulation results, at the same time the measured cutting force values deviated somewhat with simulated values. A comparison between the simulated values with the CSM model revealed that the overall results were slightly higher than those of the CSM model and closer to the experimental values. A parametric sensitivity analysis of the simulation model on rock strength, excavation loading rate, and blade width concluded that, under the same penetration depth, the normal force increased with the increase of the aforementioned factors, while the impact of the excavation loading rate on the normal force was relatively small.