In order to fabricate the metal matrix composites by low-pressure infiltration by gravity casting machine, the preform made from FeCrSi fiber with 40μm and matrix of A336.0 aluminum alloy was used. The volume fraction of fiber in preform was about 20%. The temperatures of die, preform and molten alloy were 200 oC, 400 oC and 750 oC, respectively. By controlling the infiltration of molten aluminum alloy to one direction by using barrier plate, the quantity of pores caused by curling of air degrades dramatically. Molten aluminum alloy was able to infiltrate at low pressure of 0.2MPa. As increasing the pressure, porosity in composites decreased. The composite with no pores was obtained by barrier plate and 0.8 MPa of molten alloy pressure. This composite had high strength at high temperature of 200-400oC.