To explore the mechanism of Chinese prescription Pingtang Shumu powder in treating diabetes by screening it in high-flux aldose reductase models.Methods：High-flux aldose reductase model was used to screen Pingtang Shumu powder, so as to study on its exhibition effect on aldose reductase.Results：Pingtang Shumu powder had strong exhibition effect on aldose reductase with the Icso of 0.8g/L.Conclusion：The mechanism of Chinese prescription of Pingtang Shumu powder treating chronic complications of diabetes is to exhibit the activity of aldose reductase.