In this paper, Ni 0.6 Si 0.2 Al 0.6 Mn 1.6 O 4 compounds with negative temperature coefficient (NTC) property were fabricated using NiO, SiO 2 , MnO 2 and Al 2 O 3 as raw materials. The effect of ball milling time on phase composition, microstructure and electrical stability of the compounds was studied. The results showed that the particle size of calcined powder decreased with the increase of ball-milling time, resulting in a decreased B 25/85 constant, activation energy and resistance drift ΔR/R 0 (%) of the Ni 0.6 Si 0.2 Al 0.6 Mn 1.6 O 4 compounds. Meanwhile, it was found that activation energy increased with the decrease of the density of the compounds, and the resistance drift ΔR/R 0 (%) was less than 0.02% when the ball-milling time reached to 48h.