The invention relates to a setting load keeping system of a mining hydraulic support. The existing setting load keeping system of the hydraulic support is high in energy consumption and short in life, and therefore, the setting load keeping system of the mining hydraulic support comprises a PLC and a plurality of setting load keeping and controlling units; each setting load keeping and controlling unit comprises a duplex hydraulic control one-way valve, a hydraulic liquid compensation device, a pressure sensor and an electric control valve. Each hydraulic liquid compensation device comprises an eight-channel selection reversing valve and an asymmetric one-piece piston mechanism. The setting load can be automatically kept within the preset range by arranging a pump station high-pressure liquid commonly prepared in an underground coal mine and used as a power source, the original PLC of the hydraulic support and the like and only additionally providing the eight-channel selection reversing valve and the asymmetric one-piece piston mechanism; and the setting load keeping system has the advantages of scientific design, simplicity, durability, low energy consumption and long service life and is suitable for various mines requiring hydraulic supports.