Abstract: The water and sediment regulation is an important countermeasure of managing Yellow River． By analyzing the changing process of water and sand discharge， and using the interpolation and the fitting mathematic theory， based on matlab software， the fucntion of sand discharge， time and tonnage is obtained． And numerical integration is calculated to get total sand discharge． The result of imitating the data obtained shows that it is important for analyzing and predicting the experiment of water and sand adjustment．