NOVELTY - A micro-emulsion method for preparing nanometer cathode involves mixing oil phase, surfactant and surface active agent, stirring and dividing into solution (A) and solution (B). Rare-earth nitrate and nickel nitrate are dissolved in de-ionized water and mixed with solution (A) to obtain micro-emulsion (a). Potassium hydroxide or sodium hydroxide is dissolved in de-ionized and mixed with solution (B) to obtain micro-emulsion (b). The obtained micro emulsions (a, b) are mixed, stirred, centrifuged and washed, and the obtained solid phase is sintered to obtain a nanometer cathode.    USE - Micro-emulsion method for preparing a nanometer cathode for a solid oxide fuel cell.    ADVANTAGE - The method enables providing the nanometer cathode with improved chemical stability and polarization resistance.    DETAILED DESCRIPTION - A micro-emulsion method for preparing a nanometer cathode involves mixing 5-20 ml oil phase, 2-8 g surfactant and 0.5-3 ml surface active agent, stirring, and dividing into solution (A) and solution (B). 1.8 g Rare-earth nitrate and 0.5-2.5 g nickel nitrate are dissolved in 10-100 ml de-ionized water, stirred and mixed with solution (A) to obtain micro-emulsion (a). Potassium hydroxide or sodium hydroxide is dissolved in de-ionized water to from a mixture having concentration of 0.5-10 mol/l, and the obtained mixture is mixed with the solution (B) to obtain micro-emulsion (b). The obtained micro emulsions (a,b) are mixed at 20-40 degrees C, stirred, reacted for 2-6 hours, maintained for 1-5 hours, centrifuged at 5-10 degrees C/minute and washed to obtain solid phase. The obtained solid phase is sintered at 600-900 degrees C for 6-12 hours to obtain a nanometer cathode containing nickel complex oxide (X2NiO4, where X is lanthanum, praseodymium, neodymium, samarium or europium). The oil phase is octane, pentane, hexane or cyclohexane. The surface active agent is hexadecyl trimethyl ammonium bromide, sodium dodecyl benzene sulfonate, polyethylene glycol or Span 80 (RTM: Sorbian Monooleate). The auxiliary surfactant is n-butyl alcohol, isobutyl alcohol, n-amyl alcohol, isoamylol or n-hexanol. The rare-earth nitrate is lanthanum nitrate (La(NO3)3), praseodymium nitrate (Pr(NO3)3), neodymium nitrate (Nd(NO3)3), samarium nitrate (Sm(NO3)3) or europium nitrate (Eu(NO3)3).