Abstract: This paper studied the effect of surface microstructure on wettability of flux suspension with the equipment of OM, Wetting Angle Tester and Surface Tensiometer. Experiment results and analysis show that flux suspension can adhesional wet or soak on the surface microstructure of brazing filler metal which is treated by scrubbing,scrubbing+finish rolling, but can't self wetting. Compared with scrubbing filler metals, scrub+finishing filler metals have lager contact angle hysteresis, adhesive quality of flux suspension. Adhesion layer is well distributed, and has less shrinkage hole. The adhesion work and adhesion tension are 106.39, 29.89 and 110.28, 33.78 mN/m, when flux suspension is wetting brazing filler metals treated respectively by scrubbing、scrubbing+finish rolling. With larger adhesion work and adhesion tension of scrub+finishing filler metals result in larger adhesive quality of flux suspension,well-distributed adhesion layer and less shrinkage hole.