A model was established based on the total flight distance and redundant coverage of agricultural UAV to solve the problems of agricultural UAV’s plant protection operation in irregular area. Taking the heading angle of UAV’s plant protection operation as the optimization objective and considering the situation of obstacles,the application model was solved by the method of fusion of differential evolution algorithm and quantum annealing algorithm. The implementation of the algorithm was analyzed and MATLAB simulation test was conducted. The results showed that the total flight distance was reduced by 101.52 m and 73.00 m. The turning path was reduced by 43.02 m and 43.10 m. The redundant coverage was reduced by 22.35% and 12.79%,compared with that of the unplanned and differential evolution algorithm in the set farmland environment without obstacles according to the planning. The total flight distance was reduced by 73.24 m and 24.54 m. The turning path was reduced by 52.50 m and 12.72 m. The redundant coverage was reduced by 72.34% and 23.52%,and other indicators was reduced as well. The simulation results showed that DEQA algorithm can plan the path of farmland area. It will provide technical support for planning the path of agricultural UAV.