PURPOSE: To develop the titled alloy having excellent strength and plastic workability by sintering Al-Si-Mn alloy powders having specific compsn. by powder metallurgy.

CONSTITUTION: The molten metal of the Al alloy having the compsn. contg., by weight, 12W30% Si, 2W15% Mn (where the total contents of Si and Mn are regulated to ≤40%), 0.5W8% Cu and 0.1W3% Mg or furthermore contg. at least one kind among each ≤4% W, Cr, Co, Zr, Mo, V, Ti, Li, Cl and Hf is quenched at ≥102°C/sec cooling ratio into the powders of about ≤100 mesh. Said Al alloy powders are sintered by a powder extruding method, powder forging method, etc., by which the Al sintered alloy having high strength and excellent plastic workability is produced.