The invention provides a method for preparing a nanocomposite cathode material of a solid oxide fuel cell through an impregnation method. The method comprises the following steps of adopting a silk screen print method, coating the surface of a YSZ electrolyte with YSZ-LSM composite slurry, and conducting high-temperature sintering to prepare a cathode framework which is in symmetry about LSM-YSZ/YSZ/LSM-YSZ; preparing a 0.1-0.5 mol/L YDC impregnation solution; soaking the cathode framework into the YDC impregnation solution and vacuating the cathode framework; drying and moving the cathode framework into a high-temperature furnace to be roasted for 1-4 h at the temperature of 500-800 DEG C, so that nitrate is converted into YDC nanometer particles; repeating step 3 and step 4 to prepare the nanocomposite cathode material. By means of the solution impregnation method, polarization resistance of a cathode within a middle temperature range can be greatly lowered, and the output performance of a unit cell is improved.