The invention relates to brazing filler metal for connecting copper and stainless steel, application of the brazing filler metal and a method for welding a silencer and belongs to the field of brazing filler metal and silencer welding methods. The brazing filler metal comprises, by weight, 26-34 percent of Cu, 34-35 percent of Ag, 5-8 percent of Co, 2-4.5 percent of Li, 1-1.5 percent of Sn, 0.2-1.8 percent of Ni, 1.8-2 percent of B, 0.5-1.3 percent of Mn, 0.1-1.4 percent of Si, 0.03-0.16 percent of mischmetal and the balance of Zn. The mischmetal is composed of La and Pr, the mass ratio of La and Pr is equal to the mass ratio of Cu and Ag. When the brazing filler metal for connecting the copper and the stainless steel is applied to welding of the silencer, flames are utilized for welding, the requirement for welding is met, meanwhile, welding efficiency is high, production cost is low, a noise reduction effect after the silencer is welded is good, and the service life of the silencer is prolonged.