In recent years, drones have been explored as a potential tool for pollination support in hybrid rice breeding. However, the limited flight endurance of existing electrical agricultural drones necessitates frequent battery replacements, hindering the efficient utilization of the limited effective pollination time window and reducing pollination efficiency. To address the limited endurance of drones in pollination tasks and optimize operational parameters to enhance pollination efficiency, a supplementary pollination drone was designed with extendable flight duration, utilizing a time-sharing parallel power distribution scheme with multiple battery packs, achieving a maximum flight endurance of 50 min. To improve the pollination effectiveness of the prototype, a numerical simulation of the downwash airflow generated by the rotors was conducted by using the Lattice Boltzmann method (LBM). The optimal flight parameters of the prototype were found to be a speed of 4.5 m / s and an altitude of 2 m above the male parental canopy. Field experiments were conducted to validate the prototype’s pollination effectiveness and the optimal flight parameters by comparing three drones: the prototype, a quadrotor, and a hexacopter. Data were collected in four dimensions: average pollen grain count per single field of view, fruiting rate, yield, and endurance time for standardized deviation analysis. Results showed that the flight endurance (42 min), the pollination efficiency (10.5 hm 2 per flight), the averaged pollen grain count (6.98 grains per view, meeting the agronomic requirement of at least 3 grains ), the yield ( 1 996.5 kg / hm 2 ) and the comprehensive score of designed drone were better than two comparison drones. The research result may serve as a reference for enhancing the efficiency of drone supplementary pollination in hybrid rice breeding.