We have synthesized ferromagnetic ${ au}$-phase $Mn_{54}Al_{46}/{alpha}$-phase $Fe_{65}Co_{35}$ composite by annealing a mixture of paramagnetic ${varepsilon}$-phase $Mn_{54}Al_{46}$ and ferromagnetic ${alpha}$-phase $Fe_{65}Co_{35}$ particles at $650^{circ}C$. The volume fraction ($f_h$) of hard ${ au}$-phase $Mn_{54}Al_{46}$ of the composite was varied from 0 to 1. During the annealing, magnetic phase transformation occurred from paramagnetic ${varepsilon}$-phase to ferromagnetic ${ au}$-phase $Mn_{54}Al_{46}$. The magnetization and coercivity of the composite monotonically decreased and increased, respectively, as the $f_h$ increased. These results are in good agreement with our proposed composition dependent coercivity and modified magnetization equations.