The invention relates to a multi-silver brazing filler metal containing manganese and tin, which consists of Ag, Cu, Sn, Mn, Ni and Zn, wherein the weight percentages of all the components are as follows: 19-22.5 wt% of Ag, 28-36 wt% of Zn, 36-40 wt% of Cu, 1.0-3.0 wt% of Sn, 3.5-6.5 wt% of Mn, 0.5-2.0 wt% of Ni, and 0.01-0.3 wt% of microelement R; and the microelement R is one of lanthanum, cerium and silicon, or consists of more than one of the three. The invention further comprises a preparation method of the multi-silver brazing filler metal; a medium-frequency smelting furnace is adopted to smelt and cast; all the components are added for smelting according to the sequence of Ag, Cu, Ni, Sn, Mn, Zn and Cu-R alloy; and then, the multi-silver brazing filler metal is prepared through casting, saw stripping, extrusion, drawing, molding and cleaning processes. Compared with the prior art, the multi-silver brazing filler metal has the following advantages and effects: (1) the multi-silver brazing filler metal can be used for replacing BAg45CuZnCd and Bag45CuZnCd silver brazing filler metals; the silver content is obviously reduced; the performance index parameters are approximate to that of BAg45CuZnCd and Bag45CuZnCd; and the cost performance is excellent; (2) when red copper, brass and stainless steel are brazed, the mechanical performance is excellent; (3) the brazing filler metal is better in processing plasticity; and (4) the product melting temperature is 700-770 DEG C.