Butachlor usage is increasing due to the increasing demand for agricultural products. However, it has toxic effects on surface and underground water. The experiment was conducted under visible light and the effects of parameters such as pH, adsorbent quantity, contact time, and the initial concentration of pesticides were investigated on the degradation of different pesticide solutions. The optimum dosing for ZnO and TiO₂ was 0.5 g/L. Degradation by ZnO reached 96.3% and that by TiO₂ reached 98.5%. The degradation effect of pH change was also analyzed and found to be higher in the basic region. The COD value was reduced effectively with TiO₂. The results showed that TiO₂ is more effective for degradation.