The amine functionalized $CoFe_2O_4$ nanoparticles were prepared by thermal decomposition method at reflux temperatures $160^{circ}C$ and $172^{circ}C$. The obtained $CoFe_2O_4$ nanoparticles at $160^{circ}C$ reflux temperature show aggregation free poly-dispersed nanoparticles in 4-15 nm range. In an elevated reflux temperature of $172^{circ}C$, $CoFe_2O_4$ show aggregated poly-dispersed nanoparticles in the size range of 20-46 nm. The saturation magnetization value at 300 K exhibited 51 emu/g at reflux temperature of $160^{circ}C$. However, the sample synthesized at an elevated temperature of $172^{circ}C$ has shown a coercive field value of 560 Oe with saturation magnetization of 68 emu/g.