The photo catalytic degradation of 8-anilin-1-Naphthalene sulfonic acid in water is carried out with TiO2photocatalyst.The influencing factors such as adsorption amount of 8-anilin-1-Naphthalene sulfonic acid by TiO2 in some time,amount of TiO2catalyst used,8-anilin-1-Naphthalene sulfonic acid concentration,pH value,illumination time etc on the effect of the degradation are studied.The test shows that 8-anilin-1-Naphthalene sulfonic acid hardly catalyze reaction condition no ultraviolet radiation,but the surface adsorption reaction is central about 30 minute,8-anilin-1-Naphthalene sulfonic acidl is degraded for about 95% after 5 to 7 hours,10mg/L,pH value for 4 to 6,amount of TiO2 catalyst for 2.5~3.0 g/L.