Abstract: At present, most of the detection methods for pesticide spray deposition cannot directly and quickly detect the deposition distribution parameters of the droplets on the leaves. This has an impact on the real-time evaluation of the operation effect of the plant protection spray machinery and the efficiency of feedback and adjustment of the operation parameters. In response to this problem, this paper designs a foliar droplet deposition detection system based on fluorescence response and image processing. The test results show that the average error of the monitoring system in this paper is 4. 08% compared to the processing results of ImageJ on the coverage rate of fog droplets on the leaves; Between 2. 46%and 4. 69%,the average error is 4. 01%;the fluorescent reagents used can meet the needs of field work. Using the detection system designed in this paper,the rapid and non-destructive detection of leaf droplet deposition parameters can be achieved.