The chaotic disturbance phenomenon will occur in peculiar circumstances to the unmanned aerial vehicle (UAV) system. In this paper, the authors have discussed the condition of this phenomenon, analyzed its causes through the entire environment simulation and the concrete flight practice, and applied the on-line strategy to establish a mathematical model according to the system disturbance factor. A mathematical relation among the chaotic factors of this peculiar phenomenon has been given with regard to the experiments, and finally a solution is proposed in view of the disturbance factorpsilas characteristics, moreover, the validity of this plan is further confirmed through the simulation and the flight practice.