Abstract: According to the researches about the root distributions of mature grape, the characteristics of root water uptake and the laws of water consumption, it can be provided technical support for formulating the optimum irrigation system, proposing reasonable water management pattern and creating technical system of high-efficiency utilization of water. Based on analyzing the characteristic of water uptake and the measured data of the grape root distribution under condition of irrigation, a meshless numerical simulation model for one-dimensional water flow in unsaturated soils and one-dimensional root distribution function of grape were introduced in this paper. Further, the root distribution function and the other empirical root distribution functions were applied to numerical simulation model to demonstrate the appropriateness. According to the comparison between the results of dynamic simulation and data of field experiment, it shows that the simulated values of fitting root distribution, exponential root distribution, linear root distribution and piecewise root distribution are coincide well with measured values, and all of the relative errors are below 1%. However, compared with other root distribution functions, the error of exponential root distribution is larger. Therefore the fitting root distribution and the meshless numerical model can simulate the root water uptake of grape and the soil water movement in extremely arid region well. Moreover, under the condition of the shortage of the field root length distribution, linear root distribution and piecewise root distribution can be used to describe the practical root distribution of grape, and provide reference for using one-dimensional simple root distribution model to analyze the characteristic of grape water uptake under irrigation condition.