The present study has investigated the effect of colour and optical property for chemical conversion of nano-scale metered copper powder under sonication. The experimental results found that the sequence of colour change according to the reaction time from black (CuO), yellow (Cu2O) and then turn into aquamarine (cuprous oxide and hydroxide copper chloride compound). Additional, the nano-scale metered copper powder having 62% the IR rejection within 800-1200nm.When the conversion coating formed on the surface of powder will reduce the IR rejection, but the UV rejection and the visible light transmittance is not affected.