The 3×1 fused tapered fiber bundle (FTFB) signal combiner consisting of three signal fibers and a multi-mode output fiber was studied. The simulation results indicate that the transfer efficiency and output beam quality are getting better with longer taper length. Moreover, transfer efficiency for low-order mode launching is higher than that for high-order mode launching. A 3×1 signal combiner with taper length of 10 mm was fabricated in experiment. The input beam with high beam quality results in high transfer efficiency, which agrees with the simulation results. The transfer efficiency of 96.6%, total output power of 602 W and output beam quality of Mx2=10.5, My2=9.7 were achieved as two fiber lasers with 258 W and 365 W were combined by the FTFB signal combiner.