The objective of this work was to provide the efficiency of visible light assisted Fenton oxidation for the treatment of natural gas industry wastewater containing DIPA. Different parameters were studied for the degradation of DIPA including light intensities, H2O2 and initial DIPA concentrations. From the results it was found that the optimum hydrogen peroxide concentration was 1.0 M for both light intensities. Whereas, for different DIPA concentrations depending on the light intensities, 300 W gave the higher COD removal (60.64), which was concluded as the more efficient light source compared to 500 W. © (2014) Trans Tech Publications, Switzerland.