The study of correlation of environmental factors and the plant communities along 14 locations of the fast-fl owing streams in Peninsular Thailand was carried out from April until August 2011 on calcareous and granitic types of bedrock. The main focus of this study was gathering environmental data of the fast-fl owing streams in order to understand the correlation of the environment and the plant communities along the streams. Eleven physical factors were selected, three described as environmental factors and eight as physiographic. The results of the CCA analysis suggested that the plant communities had the highest correlation with the water pH due to the type of the bedrock. According to results of correlation, three groups of plant species and plots could be recognized. Other factors that also had high correlation towards the plant communities were among the light intensity as well as stream depth and width. More studies on the species composition, their microhabitat preferences with more details are needed to be studied in future in order to support the mentioned plant communities along the fast-flowing stream in Peninsular Thailand.