A positive electrode material is provided, which includes: lithium manganese iron phosphate and carbon, the carbon is coated on the surface of the particle of the lithium manganese iron phosphate; the carbon accounts for 1.4% to 4.7% of the total mass of the positive electrode material. A preparation method of positive electrode material includes the following steps: after mixing and drying carbon source, manganese source, lithium source, iron source, doping element and phosphorus source, performing pre-sintering and pre-fusion at the first stage temperature, then increasing the temperature to the second stage temperature to continue sintering to obtain the positive electrode material. A positive electrode sheet is further provided, and a raw material for preparing the positive electrode sheet includes the positive electrode material described above.