Abstract: The disclosure relates to the technical field of electrolysis cells, and in particular to a solid oxide electrolysis cell (SOEC) and a preparation method thereof. The SOEC provided by the disclosure adopts an n-type TiO2 layer and a p-type La0.6Sr0.4Co0.2Fe0.8O3?? layer as an electrolyte layer. Although the n-type TiO2 and the p-type La0.6Sr0.4Co0.2Fe0.8O3?? have both ionic and electronic conductivities, the electric field effect of a PN junction between the two layers can effectively cut off the transmission of intermediate layer electrons and enable ions to rapidly pass through. The SOEC can effectively avoid short circuit and exhibit excellent performance. Furthermore, the above structure allows the SOEC to have a stable performance output, and the SOEC can be produced on a large scale due to low material cost.