With the aim to study the point of run-off and the maximum retention of spray liquid on cucumber leaves in greenhouse, the spraying experiment was performed with various charged voltage and spray volume. Taking the barbette model pressure atomization axial-flow air-carried high-voltage electrostatic spraying system as the experiment platform, the retention volume on cucumber leaves surface was measured by micro-weighing method. The factors on the retention volume were analyzed based on basic theory of Young’s equation, including spray distance, droplet contact angle and spray volume. The results show that with the increasing distance, point of run-off and maximum retention rises firstly and then declines; the contact angle θ, adhesion force β, adhesion work Wa, critical surface tension γ0 is 85.07°, 6.17mN/m, 77.97mJ/m2, 61.23mN/m, respectively; the retention volume reaches the peak in spray volume range from 1.26kL/hm2to 3.36kL/hm2, and then reduces and gradually stabilizes with the increasing spray volume.