Abstract: High summer temperatures in greenhouses often induce heat stress in crops, disrupting the balance between photosynthesis and respiration. Micro-spray (MS) is an effective evaporative cooling technology, but its regulatory mechanisms on crop microenvironments and physiological responses remain unclear. This study aimed to investigate how intermittent MS affects leaf surface water interception, canopy cooling, and photosynthetic performance under high-temperature conditions. A greenhouse experiment was conducted with tomato plants (Hezuo 908) grown in a Venlo-type glasshouse in Zhenjiang, Jiangsu Province, China. MS was triggered when indoor air temperature exceeded 30 ℃ and operated for 1 minute at the beginning of each hour from 10:00 to 15:00. Canopy air temperature and humidity were continuously monitored. Leaf surface intercepted water was recorded by time-lapse imaging, while leaf temperature and the actual photochemical quantum yield of photosystem Ⅱ (Y(Ⅱ)) were measured using a chlorophyll fluorescence monitoring system. Two distinct leaf interception forms were observed after MS application: droplet-type (LI-WD) and film-type (LI-WF). LI-WD occurred at canopy temperatures of 30～42 ℃ and vapor pressure deficit (VPD) of 3.0～5.0 kPa, whereas LI-WF occurred at 42～46 ℃ and VPD of 5.0～7.5 kPa. The threshold for the transition between the two forms was approximately 42 ℃. The initial coverage of LI-WD was significantly lower than that of LI-WF (31.6% vs 99.9%). Evaporation dynamics also differed markedly: LI-WD exhibited a linear decline in coverage (R²=0.71), indicating stable evaporation, while LI-WF followed an inverse S-shaped decline (R²=0.97), indicating a rapid but short-lived evaporation process. The two interception forms produced contrasting cooling effects. Under LI-WD, canopy air temperature decreased by 1.72±0.76 ℃ and the cooling effect lasted 25.2±4.1 min; under LI-WF, the decrease was only 0.74±0.21 ℃ and lasted 12.3±2.5 min. Leaf temperature under both forms showed three successive stages (decline, stable low-temperature maintenance, and recovery), but the stable period under LI-WD was significantly longer than that under LI-WF (22.5 min vs. 11.2 min). Notably, leaf temperature responded to MS evaporative cooling earlier than canopy air temperature (by 9～20 min). Y(Ⅱ) increased synchronously with leaf cooling: under LI-WD, the mean Y(Ⅱ) increase was 0.120±0.056 and lasted about 30 min; under LI-WF, the increase was 0.080±0.048 and lasted about 18 min. In conclusion, intermittent MS can generate two distinct evaporative cooling pathways controlled by initial thermal conditions. The droplet-type pathway provides more stable evaporation, longer cooling duration, and stronger physiological protection than the film-type pathway. Leaf temperature can serve as a rapid and reliable indicator for evaluating the physiological effectiveness of greenhouse MS cooling.