The polymeric scale inhibitor MA/AM/HPA was synthesized by aqueous radical polymerization with ammonium persulfate as initiator，maleic anhydride（MA），acrylamide（AM）and hydroxypropyl acrylate（HPA）as monomers. The scale inhibition efficiency of the copolymer on calcium sulfate，calcium carbonate，barium sulfate and strontium sulfate was evaluated. MA/AM/HPA possessed a good performance up to inhibition efficiency of 95% at an assure dosage for the mentioned scale types. The impact factors including temperature，NaCl concentration，pH value and evaluation time influenced the performance of polymeric inhibitor had been studied. The results showed that MA/AM/HPA possessed good inhibition performance on calcium carbonate and barium sulfate when the pH value was from 7 to 9. At 90℃，it was need to increase the dosage of polymer in order to inhibit the formation of calcium carbonate，while it was not required to that of barium sulfate. The inhibition rate of the inhibitor on calcium carbonate and barium sulfate in high concentration of sodium chloride environment was more than 90%. The inhibition rate of MA/AM/HPA on calcium carbonate kept well in long constant thermostatic time（12—72 h），and that on barium sulfate decreased obviously. SEM and XRD analyses showed that the polymeric inhibitor had a lattice distortion on the scale crystal of barium sulfate and strontium sulfate. Beyond that the inhibition performance of the polymer in oilfield water was evaluated.