Abstract: Al88Si self-fluxing filler metal ring was prepared by hot pressed sintering. Microstructures of self-fluxing filler metal at different sintering time were analyzed. And the microstructure and mechanical properties of brazed joint withselffluxing filler metal at different sintering time were also studied. It was suggested that microstructure of self-fluxing filler metal is composed of matrix phase AlSi, block primary crystal silicium andgranular KAlF₄. The activity of flux decreases with the increase of sintering time. The microstructure of 3003 Al alloy brazed joint is composed of α-Al solid solution and aciculareutectic silicium. The wettability of self-fluxing filler metal gets worse and the amount of the crack, solid inclusion, incompletely filling, and voids increase with the increase of sintering time, which decreased the tensile strength of aluminum alloy joint.