The effect of iron addition to Cu-11.0\% Al alloy on the mechanical properties and microstructures has been investigated by using isothermal transformation technique. This investigation showed that the addition of 2\% iron to Cu-11.0\% Al alloy produced fine microstuctures and that fine ironrich precipitate particles were formed within $\alpha$ phase after proper isothermal treatments. However, the addition of 1\% iron did not have any effect on the microstructures at transformation temperature of 524$^\circ$C and 560$^\circ$C. The structure of iron-rich precipitate particles was body centered cubic (B.C.C.) with lattice parameter of 2.93A. The iron additions caused increase in ultimate tensile strength (U.T.S.) and 0.2\% offset yield strength with little effect on elongation. The specimens of fine microstructures with ironrich precipitate particles showed large U.T.S., and the maximum value of 110,000 psi was obtained. The high U.T.S. is attributed to the microstructural refinement and the iron-rich precipitate particles.