Aiming at the problem of poor droplet deposition on the back of the stems and leaves and the middle and lower parts of the plants during plant protection operations in the middle and late stages of crop growth，the sturgeon head curve was used as a bionic prototype to design and test a plant protection bionic cropping and hanging rod combined pesticide application device. Based on the bionic construction to extract the head contour curve of the sturgeon，realize the bionics of the opener blade，analyze the damage reduction mechanism of the stem and leaf, and establish the mathematical model of the stem bending and rebound through theoretical analysis to determine the width of the opener blade and the distance between the nozzles. Key structural parameters such as the distance from the tail end of the opener blade were obtained. The ADAMS simulation software was used to simulate the whole process of the contact between the opener blade and the stems，and the effect of the bionic opener blade on reducing drag and injury compared with the prototype blades was tested. Through orthogonal rotating combination experiments，the influence degree and law of structure and working parameters on traveling resistance and droplet deposition degree were discussed，and the mathematical regression model was optimized by using ant colony algorithm to obtain the Pareto optimal solution set and determine the best parameter combination, which was as follows: the traveling speed was 7.0km/h，the inclination angle was 16°， and the height was 155mm from the ground. Under these parameter combination，the traveling resistance was 38.7N，and the average droplet deposition degree was 31.5/cm2. The results were verified by field performance experiments，and the error between experiments and optimization was small；compared with the traditional method of pesticide application，the bionic plant protection opener and suspender combination device can significantly improve the deposition of fog droplets in the middle and lower parts of the plant，with a coefficient of variation of 5.3%；compared with the existing prototype the bionic opener device can increase the degree of droplet deposition by 13.6%，reduce the forward resistance by 20.7%，and had a smaller error between the trend of the movement resistance and the simulation result. This research provided design reference for the development of high-efficiency pesticide application technology for stems and leaves.