This paper’s aim is to describe the results of the phase transformation of BCuAl9Fe4 alloy after casting, quenching and aging. After casting, the microstructure of this alloy consists of [Formula: see text] phase with grain size about 100 [Formula: see text]m, mixture [Formula: see text] and the inter-metallic phase Fe3Al. However, the proportion of the [Formula: see text] phase in the casting alloy is coarse. The alloy was heated at [Formula: see text]C for 2 h then quickly cooling in water. After quenching, the microstructure of alloy shows that the grain size reduced to about 40 [Formula: see text]m. After quenching, the alloy was aged at [Formula: see text]C for 2 h, the martensite phase of this alloy decomposed into order phase ([Formula: see text] with fine grain size, dispersed in the matrix. The intermetallic phase was fine and evenly dispersed in the matrix. By TEM analysis, after heat treatment, the structure of martensite and the inter-metallic phase in this alloy which had small grain size were formed.