In order to suggest the methodology for improving the equity of flow distribution in open channel with multiple outlet, CFD simulations were carried out for actual scale distribution channel being operated in domestic G_WTP(Water Treatment Plant). Also, before and after installing the longitudinal multi hole(diameter=250 mm, 116 holes) baffle suggested by this research, turbidity measurements data were collected for evaluating the effects of hydraulic modification for inlet flow equity. From the both results, total turbidity of settled water was lowered by 30 % and equity of flow distribution was improved about 60 % compared with before hydraulic structure modification.