The present invention relates to a separating plate of solid oxide fuel cell stack. The separating plate of solid oxide fuel cell stack includes a substrate, upper and lower micro channel plates and upper and lower sealing guides. The substrate includes a fuel inflow/outflow manifold and an air inflow/outflow manifold disposed opposing to each other in a diagonal direction, a fuel channel having a pair of horizontal channels and an inclined channel connecting ends of the horizontal channels so as to connect the fuel inflow/outflow manifold, and an air channel having a pair of vertical channels and an inclined channel connecting ends of the vertical channels so as to connect the air inflow/outflow manifold. The upper and lower micro channel plates are attached to upper and lower parts of the substrate and includes a plurality of micro channels so as to distribute uniformly fuel flowing in the fuel channel and air flowing in the air channel. The upper and lower sealing guides keep a constant gap with the upper and lower micro channel plates and are attached to the upper and lower parts of the substrate.