The invention discloses a non-phosphorus corrosion and scale inhibitor suitable for the low-hardness water quality. The non-phosphorus corrosion and scale inhibitor is characterized by comprising, by weight, 15% to 20% of AMPS quadripolymer water solutions with the concentration of 30%, 10% to 15% of polyaspartic acid solutions the concentration of 50%, 5% to 10% of hydroxyl carboxylate, 5% to 15% of long-chain alkyl sulfonates, 5% to 10% of N-long-chain alkyl amino carboxylate, 1% to 5% of tungstate, 1% to 3% of zinc salt, 1% to 2% of pH stabilizers selected from sodium hydroxide or hydrochloric acid, and the balance deionized water.