To find out the relationship between the pistillate flower number and fructifying rate of Longan and the temperature and rainfall, investigation and statistical methods were applied to the study of the relationship between pistillate flower number and fructifying rate of Shixia Longan and the temperature and rainfall before or after blossom. The results indicated that the temperature on 30 days before blossom (DBB) had effect on the differentiation of flower primordium during pistillate forming, and the pistillate flower number was the highest when the average diurnal temperature was 21.0 degree. When the rainfall was less than 41.8 mm 30 DBB or was less than 57.5 mm 50 DBB, the more the rainfall, the more the pistillate flower, while the pistillate flower decreased when the rainfall was excessive. The temperature on blossom and 1-15 days after blossom (DAB) affected the pistillate flower fructifying rate. Specially, the higher the temperature on blossom, the lower the fructifying rate, while when the average diurnal temperature was lower than 20.2 degree the fructifying rate increased with the increasing of temperature. In the other hand, the higher the average diurnal temperature and lowest temperature on 1-15 DAB, the lower the fructifying rate, while when the average diurnal highest temperature was lower than 30.7 degree the fructifying rate increased with the increasing of temperature. During the period of blossom and fructify and the first physiological drop, the increasing of rainfall caused the decreasing of the pistillate flower fructifying rate.