The advantages of fractional order PID algorithm compared with traditional integer order PID control algorithm were analyzed to improve the dynamic performance of farm unmanned aerial vehicle (UAV). The fractional order PID algorithm has higher control accuracy. A cascade fractional order PID control algorithm with higher update frequency is proposed based on traditional cascade integer order PID control algorithm and comprehensive implementation difficulty. It uses fractional order PID control algorithm in inner loop and integer order PID control algorithm in outer loop. The four-rotor UAV was modeled,and the parameters of the two algorithms were tuned by genetic algorithm. After obtaining the optimal control,MATLAB/SimuLink was used to simulate and analyze. The results of simulation showed that the overshoot of the two algorithms was close to zero. The regulation time of cascade fractional order PID control algorithm and cascade integer order PID control algorithm was 0.263 s and 0.386 s,respectively.The former is 31.9% less than the latter.It is indicated that effect of the cascade fractional order PID control algorithm is better than that of the cascade integer order PID control algorithm.In order to further compare the two control algorithms,a four rotor UAV is built and tested on a multi degree of freedom test bench which can test the attitude changes of multi axis aircraft.The results showed that the settling time of the cascade fractional-order PID controller was 0.24 s shorter than that of traditional algorithm.The results of simulation and experimental showed that quality of the cascade fractional order PID control algorithm was better than that of the cascade integer order PID control algorithm.The regulation time is short and the regulation process is more stable.The results of comprehensive analyses showed that the cascade fractional order PID control algorithm can further improve the operational sensitivity,optimize the flight control performance,and improve the operation efficiency of multi rotor UAV in agricultural production when applied to agriculture.It can help reduce flight accidents as well.