The advanced dispersive type high temperature filtrate reducer used in oil well cement was synthesized with 2-acryloyl-2-methyl-propyl sulfonic (AMPS) , N, N-dimethylacrylamide (DMAA) and organic acids. When the mass fraction of synthetic filtrate reducer was 1%, the filter loss of the cement slurry was 30ml/30min at 120 °C and 49ml/30min at 150°C respectively, and the cement strength was 25MPa after 24 hours, and the rheological property of the cement slurry was well when the mass fraction of synthetic filtrate reducer was 2%, and liquidity factor was 0.85, and the consistency was 0.43. The results showed that the filtrate reducer had good dispersity and could control the fluid loss efficiently, and the ability of resistance to high temperature and salt resistance was good.