The invention discloses a novel large-inertia rotating-shaft braking system. The novel large-inertia rotating-shaft braking system comprises brake installing supports, brakes and a brake disc. In the brakes, guiding columns are installed on an installing base, the guiding columns are sleeved with base bodies, hydraulic cylinders and lower brake pads are installed on the base bodies respectively, upper brake pads are connected with piston rods of the hydraulic cylinders, and travel sensors are installed on the upper brake pads and used for detecting the thickness of the upper brake pads; the multiple brakes are installed on the multiple brake installing supports through installing bases of the brakes, the upper brake pads and the lower brake pads of all the brakes are located on the two sides of the brake disc respectively, and the multiple brakes are evenly distributed outside the circumference of the brake disc. According to the novel large-inertia rotating-shaft braking system, the multiple brakes are adopted, two brake pads are adopted for each brake, braking force is extremely large, the braking effect is quite remarkable, and the novel large-inertia rotating-shaft braking system is suitable for large-inertia rotating-shaft braking; the thickness of the brake pads is detected through the travel sensors in real time, and safety accidents caused by excessive abrasion failure of the brake pads are avoided.