Abstract: Based on the data collected from plot survey, sample tree analysis and local meteorological observation data, the water production function was modeled by taking the Robinia pseudoacacia plantations in Fangshan County and Ji County of Shanxi Province as research objects to explore the water consumption of the plantations. The quantity of annual water consumption of the stand was the independent variable, while the stand biomass, or the annual increment of the standing volume was the dependent variable in the function. Among the power function, logarithmic function, quadratic polynomial function and the linear regression equation to express the water production function for Robinia pseudoacacia plantations with different densities, the power function was the best. Whereas the power function with the annual increment of stand volume and the annual quantity of the stand water consumption showed the best fitting effect. There was no obvious regularity relating to water production function in the expressing form along with the change in stand density of the plantations.