This research was performed to investigate the relationship between environmental factors including water and plant composition. In other words, determining the most effective factors in distribution of vegetation types in Arak playa was the main aim of this study. To achieve this goal, the initial map of vegetation was provided and afterward water and vegetation sampling was done. Water parameters including K+, Na+, CL-, Mg+2, %Na (exchangeable sodium percentage), Th, SAR+2, Co3, Hco3, So4, TDS (total hardness), EC, pH, and anions (sulfates, bicarbonates and chlorates) were measured. Multivariate data analysis techniques including principal component analysis (PCA) and canonical correspondence analysis (CCA) were used to analyze the collected data. The results showed that vegetation distribution pattern was mainly related to water characteristics such as Mg+2, TDS, CL- , anion, EC and Th. it can be concluded that according to habitat conditions, ecological needs and tolerance range of each plant species have significant relationship with water properties.