The present invention relates to an electrolyte-impregnated, reinforced matrix for molten carbonate fuel cells and a manufacturing method thereof. According to the invention, the electrolyte-impregnated matrix, which comprises both the electrolyte and the reinforcing particles including a metal and an oxide, is manufactured by adding the electrolyte, as required per unit cell of a fuel cell, and the reinforcing particles including the metal and the oxide, to a slurry during the matrix preparation step, and subjecting the resulting slurry to a tape casting process. By doing so, the matrix stacking operation is facilitated, and the matrix manufacturing process is simplified. In addition, cracking caused by the difference in thermal expansion coefficient between an electrolyte sheet and the matrix can be suppressed, and thermal shock occurring during operation of the fuel cell stack can be reduced, thus improving the performance and lifetime of the fuel cell.