At present,the calculation method of sedimentation rate for domestic settling basin has two kinds of quasi static and super saturated sediment,but the twe method has not established the function relation of flow and sediment motion with universal significance.While the sediment sedimentation rate by calculation is an important basis to determine whether the settling basin length, width and bottom slope reasonable.So it is necessary to study the calculation method of sedimentation rate for settling basin sediment. Through the application empirical formula of E.A Chuck Ma-lin professor get the sedimentation rate calculated by time period method,and compared and demonstrated the two kinds of methods of quasi static sedimentation and super saturated sediment method.The results show that the sedimentation rate calculated by time interval method is basic consistent with that with quasi static sedimentation method and the super saturated sediment method, the error is not more than 5%,which indicated that time interval method of sedimentation rate is feasible.The movement law of water flow and sediment time interval method calculated by time interval method is the same with that of macro analysis of settling basin run,so the simulation of water and sediment movement of settling basin is feasible.