The invention discloses a brazing material for Mn-Cu alloy and Fe-Cr-based alloy brazing and a preparation method thereof. The brazing material comprises, by mass, 54-60% of copper, 30-35% of manganese, 5-10% of nickel and 5-10% of stannum. The preparation method of the brazing material comprises the steps of putting nickel, copper, manganese and stannum into a high-frequency furnace at a formularatio, heating and melting metal, conducting heat preservation for 2-3 h and then conducting pouring to obtain a casting ingot; heating the casting ingot cooled to the indoor temperature to 700-750 DEG C, conducting heat preservation for 8-10 h, and then putting the casting ingot in flowing cooling liquid to be quenched to the indoor temperature; and finally, removing a hardened and oxidized layeron the surface of the casting ingot, cutting the casting ingot into sheets, putting the sheets in absolute ethyl alcohol to conduct ultrasonic cleaning, and fishing out and draining off the sheets toobtain the finished brazing material. Through the brazing material provided by the invention, the technical problem that Mn-Cu alloy and Fe-Cr-based alloy brazing is difficult can be effectively solved.