Abstract: The specific double hydrogeological structure increases the difficulty of study on hydrological processes in karst area. As an important input of water cycle in the basin, to study the seasonal variation of deuterium and oxygen-18 in precipitation and their influencing factors are necessary for discussing hydrological processes, such as origin of water vapor, separation of runoff and mean residence time of water. Studies on stable deuterium and oxygen-18 isotope composition of precipitation in China have been focused a lot, but little is known about seasonal variation especially in karst area. Based on the monthly data of precipitation, temperature and deuterium and oxygen-18 isotope compositions in precipitation determined by using liquid water isotope analyzer (DLT-100) from April in 2009 to August in 2011, the distribution of rainfall and seasonal variation of stable isotopes in precipitation and their influencing factors was analyzed in the typical karst peak-cluster depression areas in Huanjiang of northwest Guangxi. Rainfall amount displayed an obviously seasonal variation in this study area, rainy season start from Mar and end to September. The rainfall amount gets a big increase shift in Mar in comparison to April. The average monthly rainfall amounts of rainy and dry season are 142.5 mm and 44.0 mm. The totally rainfall amount of rainy season contributed about 75% of whole year precipitation. The local meteoric water line is obtained from linear relationship between deuterium and oxygen-18 isotope compositions in monthly weighted precipitation. The discrepancy between local and global meteoric water lines is appealed. The local meteoric water line characterized by larger gradient and intercept relative to global meteoric water line, demonstrates that the level of unbalanced in isotopic fractionation between gas and liquid is higher than normal during the formative process of rainfall mass and evaporation give some influences. Deuterium excess range from 2.23‰ to 19.95‰ and mean annual value is 14.21‰, the distinctive values between dry and rainy seasons reflect the atmospheric water vapor of different origin. The higher value of deuterium excess in dry season appeared the stronger evaporation condition reflected. Mean monthly weighted values of deuterium and oxygen-18 in precipitation of rainy season are −47.1‰ and −7.4‰ respectively, are much lower than that of dry season. Both influences of rainfall amount and temperature on isotope values in monthly weighted precipitation are feeble, but rainfall amount effect for isotope values exist in event precipitation. Seasonal variation of deuterium and oxygen-18 isotope compositions in monthly weighted precipitation presents the characteristics of sinusoidal wave. The maximum and minimum values of deuterium and oxygen-18 are 11.6‰ and -70.8‰, -0.9‰ and -10.1‰ respectively. The varied periodicity of deuterium and oxygen-18 compositions are the same 1 year and amplitude of that are 29.5‰ and 4.5‰ respectively. They have no obviously linear relationship with precipitation and temperature, but the effects of latitude and season on isotopic compositions are significant, revealing that big-scale environmental factors affect the seasonal variation of stable isotopes primarily. Such information is helpful for the further study on the catchment-scale hydrological processes based on isotopic technique, and is important to investigate the ecohydrological effects of vegetation restoration in karst region