Effect of aging treatment on the microstructures and mechanical properties of 6N01 Aluminium alloy was investigated by differential scanning calorimetry, transmission electron microscopy, microhardness measurement and tensile test. It was found that the precipitation sequence of 6N01 Aluminium alloy was GP zone ${ ightarrow}$ metastable hexagonal $Mg_2S_i({eta}^{prime})$,${ ightarrow}$ equilibrium fcc $Mg_2S_i({eta})$, and the precipitates at peak aged condition were GP zones and ${eta}^{prime}$ phase. Microhardness changes during over aged condition showed very small decrease upon increased aging time. This result was attributed to the very slow transformation rate of ${eta}^{prime}$ to ${eta}$. Maximum hardness(116 Hv) and tensile strength(312.6MPa) with 22.3% elongation were obtained from the specimen aged at $180^{circ}C$ for 15hrs.