The invention discloses a preparation method of barium titanate PTC (positive temperature coefficient) ceramic. The preparation method comprises the following steps: (1) blending following compounds according to molar ratios: BaCO3 99 to 101, TiO2 100, Y2O3 0.1 to 0.5, and SiO2 0 to 0.01; (2) carrying out high-energy super-fine ball milling to obtain powder mixture with a particle size less than 500 nm; (3) oven-drying and pre-sintering the slurry to obtain uniformly-microdoped barium titanate powder; (4) preparing a tape-casting slurry from the powder, and preparing a membrane blank by tape casting; (5) laminating and printing an Ni internal electrode to obtain a laminated chip structure; (6) incising to obtain a device with the internal electrode; and (7) sintering in reducing atmosphere and re-oxidizing in air to obtain the desired laminated chip ceramic resistor. The grain size of the semiconductor ceramic can be reduced to 2.0 mum or less, the room temperature resistivity is between 1 to 200 omega.cm, and the ratio of maximum resistance to minimum resistance reaches 103 or higher.