Southwestern China is prone to drought hazards due to rainfall patterns shift, leading to water scarcity for engineering purposes, crop devastation, and ecosystem destruction. The effective management of rainwater resources is crucial for addressing these issues and mitigate agricultural effects induced by drought, which is vital for ensuring national food security. This study reviews the water resource characteristics and agricultural drought patterns across Yunnan, Guizhou, Sichuan, and Chongqing in Southwestern China, and examines the fundamental characteristics, specific technical approaches, and primary measures of an efficient rainwater regulation and control system in this region. Results of the study indicates that the spatiotemporal distribution of water resources is uneven in Southwestern China and the reliability of agricultural water supply urgently needs further improvement. This is due to a lack of integration among natural water systems, artificial water networks, and rainwater harvesting projects on slopes, which hinders the efficient allocation of water resources across different periods and regions. To address these challenges, it is recommended to (1) enhance the construction of large and medium-sized reservoirs and implement "five types of small water conservancy" projects, (2) develop surface runoff control technologies for different regions and environments, (3) promote ecological and clean small-watersheds management, (4) expand the adoption of water-saving irrigation technologies in agriculture, (5) establish models for utilizing rainwater resources, (6) improve sustainable mechanisms for infrastructure construction, management, and operation, and (7) provide technological support for small water conservancy projects in rural areas. These efforts will provide critical technical support to alleviate agricultural drought impacts, increase agricultural water supply, optimize water distribution, and maintain food security in Southwestern China.