Abstract: The ring of Al-12Si self-fluxing filler metals has been prepared by hot pressed sintering. The wetting property, microhardness, microscopic structure of self-fluxing on different sintering pressure were studied. The results showed that the spreading areas of the self-fluxing filler metals were affected with sintering pressure. And the spreading areas of the self-fluxing filler metals was up to 152 mm² when the sintering pressure was at 222 MPa. With increasing of the sintering pressure, the density, microhardness of the self-fluxing filler metals increased, but the tendency of increasing became slowly. The microscopic structure of self-fluxing filler metals was composed of black large lump and white small particles which was evenly distributed on the gray matrix; XRD results showed that self-fluxing filler metals was only composed of α-Al solid solution, primary crystal silicium and Nocolok filler metals, which denoted that the filler metals prepared by hot pressed sintering did not occur oxidation reactions and hydrolysis reactions. The activation of silicium ensured the high activity of filler metals.