Based on the optimization of cut-off parameters for excavation machines, using discrete element method-multi-body dynamics bi-directional coupling technique, based on numerical simulation, multi-objective optimization method, taking a certain type of roadheading machine cutting mechanism as the engineering object. Joint Pro/E, EDEM and RecurDyn to build a DEM-MBD bi-directional coupling simulation model of the cut-off process of excavation machines, investigating the effect of different working conditions on the load on the cutting head and cutting performance. Using the Box-Bohnken test method in Design Expert to design a three-factor, three-level response surface regression test with cut-off ratio energy consumption, load mean value and load fluctuation coefficient as cut-off performance evaluation indexes, reducing the three-dimensional objective to a truncated integrated evaluation degree one-dimensional merit search model by principal component method. The results show that when the transverse pendulum speed is 1.270 m/min, the speed range is 44.158 r/min, and the vertical pendulum angle is 12.232°, the integrated evaluation degree of truncation reaches 0.903.