Large-temperature-difference well cementation cement paste and preparation method thereof

The invention discloses large-temperature-difference well cementation cement paste and a preparation method thereof. The large-temperature-difference well cementation cement paste comprises the following components in parts by weight: 100 parts of oil well cement, 0.5-40 parts of a strength stabilizer, 0-50 parts of a density regulator, 5-20 parts of a reinforcing material, 2-4 parts of an early strength agent, 0.5-3.5 parts of a retarder, 2-7 parts of a fluid loss agent, 1-2 parts of a dispersing agent, 0.1-0.5 part of a defoaming agent and 40-85 parts of water. The cement paste disclosed by the invention is adjustable in density, adjustable in thickening time, good in flowing property, good in sedimentation stability, low in water loss and free of free liquid, and meets the requirements of well cementation construction; meanwhile, the 48-hour compressive strength of top cement stone is larger than 10 MPa, the applicable circulating temperature ranges from 100 DEG C to 200 DEG C, the temperature difference r