A light roofing system is formed of a substrate layer and a waterproof surface layer. The waterproof surface layer comprises a functional coating layer made of functional paint and a waterproof layer made of waterproof paint, the functional paint comprises a base material and functional materials, and the functional materials comprise an inorganic flaky material, an inorganic high-rigidity wear-resistant material, and polymer powder with good toughness. The addition amount of the inorganic flaky material accounts for 1% to 8% of the total weight of the functional paint, the addition amount of the inorganic high-rigidity wear-resistant material accounts for 2% to 15% of the total weight of the functional paint, and the addition amount of the polymer powder with good toughness accounts for 1% to 8% of the total weight of the functional paint.