Provided are a cobalt-based alloy and a cladding layer prepared from the cobalt-based alloy. The cobalt-based alloy comprises Co, Ni, Cr, Fe, Si, W, C and Al. The cobalt-based alloy is specifically prepared from, by weight, 19-22.5% of Ni, 18-19.5% of Cr, 7.5-10.5% of Al, 0.8-1.1% of Fe, 0.7-1.0% of Si, 3.0-4.4% of W, 0.6-0.9% of C, and the balance Co and smaller than 0.1% of inevitable impurities, and the mass percent of Ni and Co is greater than 0.4 but smaller than 0.56, and the mass percent of Ni and Al is greater than 2 but smaller than 2.7. The cobalt-based alloy can be used for preparing the cladding layer with high abrasion resistance performance and heat fatigue resistance performance, and the cladding layer not only can be used for repairing and enhancing a friction layer of a brake disc, but also can be used as the friction layer of the brake disc and a protection layer on the surface of other metal materials needing to bear repeated heat impact and having friction abrasion in the environments like mold cavity linings, engine pistons and inner cylinders, petroleum pipeline valve inner walls.