Based on an ab initio method, the optimization of possible geometry structures and the calculation of the adsorbed energies, charges and populations have been carried out for the adsorbed-decomposition of NO, CO and CH2O on a TiO2(110) defect surface. The orbital interaction particulars and a promising mechanism of the adsorbed-decomposition of NO on TiO2(110) (1 x 1) defect surface are proposed.