Abstract: It is difficult to transport pesticide droplet into tree canopy and deposit onto opposite of foliage.In order to solve these problems, air-assisted and electrostatic spraying was proposed.Air-assisted electrostatic spraying is a new pesticide application technology combined air-assisted spraying and electrostatic spraying technology.The charged droplets transport and deposit under theair drag force and electrostatic force, which improved the charged droplet penetration ability and deposition within the crop canopy.The influencing factors of air-assisted electrostatic spray include induced voltage, spray distance, air velocity and spray pressure.To clarify the factors influence on spray coverage.Induced voltage was set 0, 3 and 6 kV; Spray distance was 0.5, 1, 1.5 m; Axial fan frequency was 30, 40, 50 Hz; Spray pressure was 0.3, 0.4, 0.5 MPa.CCD (central composite design) and RSM (response surface methodology) were employed to analysis the four factors at three levels.29 group tests were conducted, which include 24 group analytical factors, 5 group error estimations.Design Expert Version 8 software (Stat-Ease Inc., USA) was used for experimental design, data processing and statistics.Response include positive coverage, opposite coverage and the ratio of opposite and positive coverage.The three response surface models were established by quadratic regression, model determination coefficient was 95.14%, 93.68%, 93.95% respectively.Aiming at the ratio of opposite and positive coverage and opposite coverage maximum, positive coverage less than or equal to 50%.Response surface model was adopted to optimize the working parameters at the constraint condition of induced voltage X1=6 kV, fan frequency X2∈30,50 Hz, spray distance X3∈0.5,1.5 m and spray pressure X4∈0.3, 1.5 MPa.At the same time, the models were validated at this condition, and the positive predictive coverage was 50%, the negative coverage rate was 3.69%, the ratio of opposite and positive coverage was 7.52%.The relative error was 4%, 9.25%, 16.26%, respectively.The results showed the ratio of opposite and positive coverage′s influence factors ranked from large to small wasthe induced voltage, fan frequency, spray distance and spray pressure.Opposite coverage′s influencing factors ranked from large to small wasinduced voltage, spray distance, spray pressure and fan frequency.Positive coverage′s influencing factors ranked from large to small was spray distance, spray pressure, fan frequency and induced voltage.The charged droplets were mainly affected by the air drag force and electrostatic force.The interaction among fan frequency, induction voltage, spray distance had significant effects on the response surface model.Reasonable working parameters can improve negative droplet coverage.The study can provide the basis data for design of air-assisted electrostatic spraying machine and operating parameters choose.