A novel quadripolymer scale inhibitor poly-maleic anhydride-acrylic acid-acrylamide-sodium methallyl sulforrate (PMAAS) was synthesized by solution polymerization with maleic anhydride (MA), acrylic acid (AA), acrylamide (AM), sodium methallyl sulfonate (SMAS), etc. IR spectrum shows that PMAAS contains carbonyl, hydroxyl, phosphatic and sulfonic acid group. SEM indicates that PMAAS blocks the normal growth of scale CaCO3 and CaSO4 crystals. The influences of PMAAS concentration, Ca2+ concentration, temperature and pH value of the system on the inhibition efficiency are investigated. The inhibition efficiency of PMAAS is superior to commercial inhibitors T-225 and XF-192.