In Fe-Mn-Al-based shape memory alloys, the essential strategy for obtaining good superelasticity is precipitating coherent B2 nano-particles by adding Ni element. In the present paper, we investigated the effect of Ni contents on the precipitation behavior of nano-ordered particles in Fe-Mn-Al-Ni alloys subjected to solution treatment followed by water quenching and air cooling, respectively. D0₃ nano-particles were precipitated in water-quenched and air-cooled specimens with the Ni content of 2.1 at.%. However, coherent B2 nano-particles were precipitated in the water-quenched and air-cooled specimens with the Ni contents of 4.0–10.8 at.%. In addition, their average diameters increased linearly with increasing Ni contents, and were 3.4–14.5 nm for the water-quenched specimens and 9.5–32.3 nm for the air-cooled specimens. The precipitation of B2 nano-particles cannot be suppressed even by water quenching owing to the formation of a miscibility gap after adding Ni element in Fe-Mn-Al-Ni alloys.