The invention discloses a lowering control system for a movable arm of a hydraulic excavator for mines, and relates to a hydraulic excavator. The system solves the problems that the prior art can only control the lowering speed of the movable arm and cannot utilize the impact energy generated by dead weight so as to cause energy waste. The system consists of a main pressure oil passage and a pilot control oil passage, wherein the main pressure oil passage consists of a left shunt block, a right shunt block, a left one-way throttling valve, a left movable arm cylinder, a safety valve, a right movable arm cylinder, a right one-way throttling valve and a hydraulic pipeline; and the pilot control oil passage consists of a remote control valve, an electromagnetic switching valve, a left movable arm cylinder one-way valve, a left movable arm cylinder regeneration valve, a right movable arm cylinder regeneration valve, a right movable arm cylinder one-way valve, an oil tank and a hydraulic pipeline. In the process of lowering the movable arm, the impact energy generated by lowering due to the dead weight of the movable arm is fully utilized for regeneration, so energy is saved, heating of a hydraulic system is reduced, lowering of the movable arm is quickened, and the work efficiency of the hydraulic system of the hydraulic excavator for mines is improved.