Water vapor isotopes are not only controlled by the long-term and short-term conditions of climate, but are also very sensitive to extreme synoptic conditions. Hydrogen and oxygen isotopes in atmospheric precipitation not only have a certain response to climate change at different time scales, but also have strong linkages to extreme weather events. The study of precipitation isotopes was based on long and short term sampling in the past, but the study on the changes of the stable isotopes during the extreme precipitation and the source of water vapor is relatively less. This paper takes a typhoon rainfall as an example to reveal the changes of precipitation isotope and its effect mechanism in the typhoon weather. This study analyzed the precipitation and the stable isotopes during the period of No.10 Typhoon"Matmo"that landed Fuzhou in 2014. The range of delta~(18)O in the"Matmo"precipitation is-7.2--15.4. The whole process of precipitation can be divided into three stages. At stage one (3:00 am July 23th to 12:00 am July 23th), the water vapor delta~(18)O is relative heavy (weighted average value is-7.8). At this time, the external circulation of the typhoon influenced the sampling spot. At stage two (12:00 am July 23th to 8:00 am July 24th), the water vapor delta~(18)O of sample spot become dramatically lighter (weighted average value is-13.9). The precipitation in this stage was 134.8 mm, which accounted for 78% of the precipitation in the observation period, and the effect of precipitation amount was obvious. At stage three (8:00 am July 24th to 17:00 pm July 24th), the typhoon precipitation delta~(18)O become heavy again (weighted average value is-9.2)when the precipitation gradually decreased and the typhoon moved away from Fuzhou. The analysis of water vapor flux at 850 hPa and the HYSPLIT-4 simulations of vapor transport trajectories indicated that the water vapor source were primarily from the water vapor channel in the Northwest Pacific and the water vapor channel in the bay of Bengal and the South China Sea.