Solid oxide electrolysis cell (SOEC) as an environmental-friendly device can converse the electric energy into chemical energy with high efficiency. In this paper, the progress on structure and working principle of SOEC for co-electrolyzing steam and carbon dioxide to generate syngas were reviewed. The structure of SOEC, the recent development of high temperature steam/CO2 co-electrolysis from solid oxide single electrolysis cell and cell stack were also introduced. In addition, the improvement of structure and development of novel material for increasing the electrolysis efficiency of SOEC were put forward as well.