Abstract: To investigate differences in control effects of plant protection UAV and conventional sprayers on major pests and diseases of highland barley, a field comparison experiment was conducted in Haidong City, Qinghai Province．Three treatments were established including plant protection UAV（T₁ treatment）, knapsack electric sprayer（T₂ treatment）, and blank control（CK treatment）, to compare effectiveness of two application methods on control of highland barley aphids, stripe rust, and smut disease, as well as their impact on droplet deposition characteristics, operational efficiency, and yield．Results have shown that T₁ treatment achieved an aphid control rate of 86.73% after 7 days of application, which was significantly higher than 79.24% observed in T₂ treatment．Control rates for stripe rust and smut disease were 82.15% and 78.36%, respectively, with no significant difference compared to T₂ treatment．In T₁ treatment, droplet densities in middle and lower parts of canopy were 28.65 and 15.47 droplets/cm², respectively, which were significantly higher than those in T₂ treatment．Operational efficiency of plant protection UAV was 2.67 hm²/h, which was 8.9 times that of knapsack electric sprayer．T₁ treatment yielded a 18.72% increase in yield compared to CK treatment．A comprehensive analysis has revealed that plant protection UAV exhibited excellent control efficacy and high efficiency in highland barley pests and diseases control, making them suitable for promotion and application in highland barley-producing areas on Qinghai-Tibet Plateau．