The invention discloses a medium-low temperature oil-based curing plugging slurry and a preparation method thereof, wherein the raw materials comprise, by weight, 70-110 parts of a curing agent, 0.1-0.3 part of a retarder, 5-25 parts of base oil, 1-10 parts of water, 0.05-1 part of organic soil, 10-50 parts of a weighting agent, and 0.3-1 part of an emulsifier. According to the present invention,the preparation process and the construction process of the plugging slurry are simple, the plugging slurry can be directly prepared from the oil-based drilling fluid, has good pumping property at a normal temperature, has a curing temperature of 80-100 DEG C, has pressure bearing sealing capacity of up to 3.9 MPa, and has good plugging effect.