High temperature-resistance salt-resistance oil well cement filtrate reducer

The invention discloses a high temperature-resistance salt-resistance oil well cement filtrate reducer. The raw materials used in the production of the reducer comprise AMPS(2-acrylamido-2-methyl propane sulfonic acid), acrylic acid, acrylamide, sodium hydroxide, potassium persulfate and water in a mass part ratio of 32-36:2.5-3:12-15:4-6:0.3-0.5:120. The high temperature-resistance oil well cement filtrate reducer prepared according to the formula is applicable to all-grade cement in accordance with API standards; the additive amount of the reducer in a slurry system at a high temperature of 210 DEG C is 5 to 8 percent of the total volume of slurry; and the water loss rate in well cementation can be effectively controlled within 50ml.