Abstract: The working principle of balancing valve and the force of the main valve core were analyzed; the kinematic equation of main valve core was built in this paper. Through those analysis found that the oil cylinder weight, pilot control pressure, coefficient of spring stiffness and pre tightening force have important impact to dynamic performance of balance valve. Through the force analysis of roadheader’s cutting unit, established its statics equation and got simulation curve of cutting oil cylinder loads by MATLAB software. Through the simulation curve known that the load was decreasing with the cutting head rise; when the cutting head in the bottom and top position, the force of lifting oil cylinder would get maximum and minimum respectively. Using AMESim to do dynamic simulations get the result that when the load of oil cylinder is too big,the speed fluctuation will be larger and the shake time will be longer; the diameter size of control oil damping hole has small impact to system, but the smaller it is, the smoother of spool motion; large spring stiffness can be beneficial to the stability of the system; if the spring pre-tightening force is too big, not only have disadvantage to system stable, but also produce cavitation phenomenon to the balance valve.