Copper nanoparticles are preferred as a printable conductive material in printed electronics because they cost less than noble nano particles such as gold and silver. Only disadvantage is that copper is easily oxidized, which may deteriorate the conductivity. Copper is thermodynamically unstable at atmospheric condition and is easily oxidized into either $Cu_2O$ or CuO, both of which are less conductive compared to pure copper. To alleviate these problems, we propose a sintering process using laser in the study. The laser source in this study is a laser having 532 nm wavelength and 5 W maximum output power. The size of used copper particle is 100~120 nm. In order to measure the absorptivity at 532 nm, UV visible-spectrometer was used. Copper nano ink was spin-coated on the glass substrate, and various irradiated laser powers and scan rates were applied in air. The resistivity of the conductive film, after laser sintering under the condition of air, was below $5.3{mu}{Omega}cm$ which was three times as much as that of bulk copper.