The invention relates to a phosphorus-free corrosion and scale inhibitor, which is prepared from sodium molybdate, zinc salt, citrate, triethanolamine, benzotriazole (BTA), polyaspartic acid (PASP), polyepoxysuccinic acid (PESA), AA / AMPS terpolymer, solid alkali and water. The phosphorus-free corrosion and scale inhibitor inhibits corrosion of metals by forming oxidization type and precipitation type films on the surfaces of the metals, has the effect of inhibiting scale through chelation and dispersive action on salts causing scale in cooling water, is non-toxic and phosphorus-free, has easily biodegradable major organic compositions, does not cause environmental pollution and is not limited by phosphorus in emission.