A simple template assisted sol-gel method was used to prepare nano-size CoFe2O4 powders with high specific surface area and magnetic properties. The influences of template and heat treated temperatures on the composition, microstructure, specific area, magnetic properties as well as magnetic heating rate were studied through XRD, TEM, BET, VSM and RF heat tests. The results show that adding template helps to obtain pure spinel CoFe2O4 nano-magnetic particles, and with the increase of heat treated temperature, the average grain size of the as-prepared nano-particles increases, reducing its surface area. Without template, the as-prepared nano-particles exhibit serious accumulation. After adding the template, CoFe2O4 particles are the approximate ellipsoid, and connected one by one, similar to a line, and its agglomeration decreases significantly. The average grain size of nano-sized particles obtained when adding template and calcined at 800 ℃ is about 70.0 nm, its specific surface area is 23.7 m2·g-1, its Ms equals to 79.0 emu·g-1, its Mr equals to 37.1 emu·g-1, its coercive force equals to 856.4 G, and its magnetic heating rate is 2.95 ℃·s-1. These values are all significantly higher than that of nano-sized CoFe2O4 particles obtained without template and calcined at 800 ℃. Finally, the formation process of thread-like nano-sized CoFe2O4 particles was discussed.