[Objective] Rice is the most important staple crop and needs much water resource in China, so precision water management is necessary for high efficiency rice production. [Method] Based on analysis and extraction of the research results in rice cultural theories and technologies, further on the theory of soil water balance, with soil water potential as the irrigation index, a knowledge model for precision water management in rice (KMPWM) was developed by quantifying the relationships of water demand and cultivation technologies, variety traits, and eco-environments. Furthermore, based on the system engineering theory, a decision support system for rice precision water management was established on the platform of Microsoft Visual Studio.NET 2005. [Result] KMPWM realized the functions of irrigation management scheme design and real-time regulation. The field comparison experiments at Hangzhou and Nanjing showed that the average grain yields were improved by 6.9% and 9.1%, respectively, and irrigation water use efficiencies were remarkably increased by 53.61% and 42.73%, respectively, in two eco-sites under the model-designed irrigation strategies, as compared to conventional irrigation regimes. [Conclusion] It appears that the present model has good applicability and proper guidance for rice precision water management.