In present study, density function theory was used to computed adsorption strength of toxic gases across surface of boron-nitride copper decorate nanoribbon. Gases under study was carbon mono-oxide (CO), hydro cyanide (HCN) and methane (CH4). Copper atoms has clear effect on structural and electronic properties of boron-nitride nano-ribbon especially energy gap property, it is change from insulator to semiconductor material in other hand, modify electrical conductivity. Adsorption calculation shows that methane gas molecule has more binding energy compared with other gases and this clear in distance 1 and 1.5Å from surface. HCN and CO gases molecule have chemical interaction only and this clear in distance near surface. CH4 gas molecule has more binding energy in chemical and physical interaction for distance between it and surface.