Highlights A precision regulation architecture of prataculture based on agriculture cyber-physical system (PRACPS) was proposed. The PRACPS-ALFA model was designed and implemented through the actual physical environment and Ptolemy tool. The PRACPS-ALFA has good applicability in the Ningxia irrigation area of the Yellow River. The architecture can achieve precise water regulation of forage under a complex physical environment. Abstract. Because the architecture of prataculture precision irrigation cannot dynamically track forage growth and change in future physical environments, a precision regulation architecture of prataculture based on an agriculture cyber-physical system (PRACPS) is proposed. We use the most widely planted alfalfa as an example and design an alfalfa application architecture based on the PRACPS (PRACPS-ALFA). An alfalfa growth model based on water factor was built into the PRACPS-ALFA. We discuss the construction methods of the physical space, the cyber space, and the cyber-physical interaction interfaces. The PRACPS-ALFA is designed and implemented through the actual physical environment and the Ptolemy tool. Four evaluation indices are designed to evaluate the applicability and accuracy of the architecture. Finally, through field experiments in the Ningxia irrigation area of the Yellow River, the model is validated and analyzed by the simulated and observed values of each evaluation indicator. The results show that the PRACPS-ALFA has good applicability in the Ningxia irrigation area of the Yellow River and can achieve precise water regulation of forage in a complex physical environment. Keywords: ACPS, Alfalfa, Applicability, Prataculture, Precision regulation, Ptolemy.