Exponential smoothing based on time series is one of the methods widely used in predicting,but is rarely applied in the dynamic simulation and prediction of soil moisture.In this paper,the simple exponential smoothing was used to simulate and predict daily soil moisture and soil water storage capacity of an artificial locust forest in the loess region of Western Shanxi Province,between June 1st and September 30th,2009.The results show that soil water moisture and soil water storage capacity were simulated and predicted with a reasonable accuracy level.Observations of seven different layers(0—150 cm) indicated that the prediction accuracy of soil moisture increased with soil depth.The maximum error of the predictions within the layer of 100—150 cm was less than five percent,and the most accurate prediction(with an average error of 0.1 %) were found in the layer of 120—150 cm.Compared with the predicted and measured values,it was found that rainfall,evaporation and evapotranspiration,surface runoff,plant uptake and other factors may affect the artificial locust forest soil water moisture and soil water storage capacity up to the depth of 120 cm.