The invention relates to a Fe-doped BiCuSeO thermoelectric material and a preparation method thereof. The preparation method is characterized by comprising the steps of: preparing materials accordingto an amount-of-substance ratio of bismuth oxide powder to copper powder to selenium powder: bismuth powder to iron powder being 1:3:3:(1-3y):3y, wherein 0.01<=3y = x <=0.08, mixing the powder, putting the mixed powder into a ball-milling tank, performing ball milling on the mixed powder under the condition of an inert atmosphere to prepare single-phase FexBi1-XCuSeO powder, putting the single-phase FexBi1-XCuSeO powder into a mold, placing the mold in a plasma activated sintering furnace, raising the temperature to 500-700 DEG C at a constant speed and raising the pressure to 30-100 MPa at aconstant speed simultaneously, maintaining the temperature and pressure simultaneously, then reducing the temperature to normal temperature at a constant speed and reducing the pressure to normal pressure at a constant speed simultaneously, taking out the sintered mold, and demolding to obtain the Fe-doped BiCuSeO thermoelectric material. The preparation method has the advantages of simple process, short production cycle and high production efficiency. The prepared product has the advantages of high purity, low thermal conductivity, high electrical conductivity, good electrical transmission performance, high power factor and high dimensionless thermoelectric figure of merit ZT.