This research aim to investigate kinetics of humic acid photo-transformation. This study was done under some optimum conditions: lighting time of 2 hours, using Hg lamp of low pressure (l = 254 nm), humic acid of 100 ppm and pH=9.2. it was disclosed that 97.51 % of humic acid transformed into minerals product which involved the first orde reaction, 38.4 minute half-life, the constant rate of reaction is 0.02 minutes-1 and the quantum rendement of 0.115 molecules per photons.
