Abstract: Copolymers T-400 and T-1000 containing phosphono, polyether, carboxylic groups were prepared from the monomers of acrylic acid (AA) and mono-methyl polyethylene glycol (Mn = 400，1000) acrylate (MPEGAA). The effects of inhibitor doss, concentration of Ca2+, inhibiting time, temperature, and pH on anti-scaling capacity of copolymers for CaCO3 and CaSO4 were discussed. And the differences between T-400 and T-1000 were compared. The results showed the copolymers had good effects on reducing scale depositions of CaCO3 and CaSO4. T-400 had better inhibiting capacity for CaCO3 than T-1000 when the dosage of copolymer was 12 mg/L and T-1000 had better inhibiting capacity for CaSO4 than T-400 when the dosage was 4 mg/L.