The water-free, fully synthetic, fire-resistant hydraulic fluid used in coal mine shafts is prepared based on polyol ester as the main component, compounded with lubricants, rust preventatives, viscosity improvers, defoamers, and other additives. It is miscible with mineral oil, has a high flash point and ignition point, low evaporation loss, good fire resistance, high viscosity index, excellent corrosion resistance, lubricity, and material adaptability. It is miscible with mineral oil, safe, environmentally friendly, and has a long service life. It can replace mineral oil-based lubricants for use in underground mines. It is mainly used in hydraulic systems such as the operation system, coal cutter, tunneling machine, belt conveyor, side-dump rock loader, and roof bolter. This product possesses the following technical characteristics: 1. High flash point and ignition point, with good flame resistance; 2. High viscosity index, excellent stability, rust resistance, lubricity, and shear resistance; 3. The product is biodegradable.