In the present study, a reliable and very sensitive sensor for the determination of ultra-trace of Cu(II) is proposed. Copper was determined by anodic differential pulse stripping voltammetry based on the adsorption collection of the Cu(II) on an encapsulated Schiff base onto multiwalled carbon nanotube paste working electrode. The variation of peak current with pH and several instrumental parameters such as accumulation time, accumulation potential and scan rate, were optimized. Under optimized condition, the relationship between the peak current and copper ion concentration is linear which is used as analytical signal. The method was applied to the determination of copper ion in river water, city water, and bottled water and drinking water samples with satisfactory results.