Abstract: During early spring， early\|maturing superior tea tends to suffer severe late frost damage. Temperature variation of underlying surface of tea plantation was studied under late frost in order to develop frost protection methods and technologies. On the basis of analysis on the microclimate of tea fields and late frost occurrence， experiments were conducted to measure the air temperature within 12 m high above the tea canopy. The spatial\|temporal distribution of air temperature and the influence of different weather conditions on frost occurrence were analyzed. The results showed that the radiation frost was prone to occur with thermal inversion during clear spring night when air temperature was around 0℃ and wind speed was less than 05 m·s-1. But there was no frost during rainy or cloudy nights or when the wind speed was above 20 m·s-1. Thermal inversion appeared around 17：30 and inversion intensity increased rapidly. The maximum inversion difference was up to 99℃. The variation of inversion intensity was relatively stable during 20∶00-6∶00 with the average volatility of 141%. Then inversion intensity weakened sharply， and thermal inversion almost disappeared around 8：00. Air temperature near ground was clearly stratified vertically. The temperature rising rate within 0-30 m and 60-75 m high was 151 and 158 ℃·m-1， which was greater， but was unremarkable within the height of 30-60 m and 75-120 m. Therefore， 60-75 m would be the optimal height for the installation of frost protection fans.

Key words: Camellia sinesis, late frost, air temperature, thermal inversion