Application of thermal diffusion technology to measure the sap flow of Pinus massoniana in serious soil erosion areas in Changting county during the typhoon, the results showed that:typhoon brought high-intensity rainfall and strong winds which suppressed transpiration;the rainfall didn't improve plant availability moisture;photosynthesis and water physiology before and after the typhoon had no significant difference;the sap flow density during the typhoon was significantly related (P<0.01) with the environmental factors as:solar radiation, air temperature and vapor pressure deficit, while on sunny days were:air temperature, solar radiation, relative humidity and vapor pressure deficit.Studies have shown that:typhoon did not improve the plant available water, nor destroy the physiological activities of Pinus massoniana.