The Southern Central Vietnam (only include Ninh Thuan and Binh Thuan province) is the typical driest region in Vietnam Nam Trung characterized by drought and desertification. And, to date, global climate change will make that to become more horribly, that affected not quite small on agriculture. The article introduced the results of using ETo Calculator and GIS through processing meteorological data of 6 meteorological stations for 30 years (1980-2007) to identify the wet periods and also divide the regions at the other levels. By calculating the wet period, the rainy time before and after the wet period, the authors identified the advantage planting time (PETo) and the available planting time (P0,5*ETo) and the transitional period. Accompany with annual rainfall and annual ETo of the case study, the authors built the suitable planting time charts for each meteorological stations on the annual rainfall map. In addition, base on that, the authors clas,sified the regions having the advantage planting time. The results will play important role in agriculture (select plant structure, agriculture calendar, adapting to the meoteorological conditions), agricultural zoning adapting to the climate of each local to adjusting to global climate change.