Disclosed is a reinforced matrix for a molten carbonate fuel cell comprising a porous aluminum support and a lithium aluminate tape-cast on the porous aluminum support. Further, disclosed is a method for preparing the molten carbonate fuel cell comprising the reinforced matrix comprising steps of tape-casting a lithium aluminate on a porous aluminum support so as to prepare a reinforced matrix (S1), making a unit cell or a stack of the unit cells using the reinforced matrix (S2) and heat treating the unit cell or the stack so as to oxidize aluminum in the support into lithium aluminate (S3). According to the present invention, the method is simple and economic, and the mass production of the matrix is easy, and strength of the matrix can be increased effectively and therefore there is no worry about fracture or crack.