Abstract: To address the low water-use efficiency and extensive traditional irrigation practices in maize cultivation in the Chishui area of Guizhou Province, this study compared the effects of Internet of Things（IoT)-based precision irrigation and traditional irrigation on maize yield, quality, and economic benefits. A field comparative trial was conducted in 2024 in Fuxing Town, Chishui City, Guizhou Province, using the locally dominant cultivar Yunuo No.7 as the test material. An IoT-based precision irrigation treatment group（T）and a traditional irrigation control group（CK）were established. In the treatment group, soil moisture sensors and meteorological monitoring stations were deployed to build an intelligent irrigation decision-making system based on the Crop Water Stress Index（CWSI), adopting a distributed three-layer architecture（perception layer–network layer–application layer）to achieve precise water management throughout the maize growth period via drip irrigation. In the control group, local farmers applied traditional flood irrigation, subjectively determining irrigation timing and volume based on sensory indicators such as topsoil cracking, leaf wilting, and weather conditions, with 600–900 m³·hm⁻² applied per irrigation event, 3–4 irrigation events per growth cycle, and no fixed irrigation schedule. The monitoring period covered the entire maize growth cycle（120 days), and system operational stability indicators included sensor network coverage, data transmission success rate, system availability, average response time, and equipment failure rate. Results showed that the IoT-based precision irrigation system operated stably, with 100% sensor network coverage, a 98.5% data transmission success rate, 99.2% system availability, and a 94.6% irrigation decision accuracy rate. Seedling emergence uniformity in the treatment group reached 92%, 17.9% higher than in the control group（78%); maturity was reached at 120–122 days, 3–5 days earlier than in the control group（125 days). Maize yield in the treatment group reached 6,200 kg·hm⁻², a significant increase of 15.2% over the control group（5,380 kg·hm⁻²)（P＜0.05); effective panicle number increased by 8.7%, kernels per ear increased by 6.4%, and thousand-kernel weight showed no significant difference between the two groups（P＞0.05). Grain moisture content decreased by 8.1%（P＜0.05), protein content increased by 8.2%, starch content increased by 2.3%, and test weight increased by 17 g·L⁻¹（a 2.3% increase). The marketable rate rose from 82% to 90%, irrigation water use decreased by 23%, water-use efficiency increased from 52% to 78%, net benefit increased by 4,442.5 yuan·hm⁻², and the payback period of the IoT precision irrigation system was approximately 0.79 years. The IoT-based precision irrigation system is technically feasible and operationally stable for mountainous maize cultivation, significantly improving maize yield and quality, with notable water-saving and efficiency-enhancing effects, a short payback period, and significant economic benefits, providing a technical reference and decision-making basis for maize production in the hilly and mountainous regions of southwestern China.