For evaluation of the reaction of twenty red beans ecotypes to drought stress, an experiment was conducted in split plot as Randomized Complete Block Design with 3 replications in 2016-2017 at research field of Graduate University of Advanced Technology, Kerman, Iran. In this study, the main plots were three irrigation levels and sub-plot were twenty red beans ecotypes which they are sub-population from different regions of Iran. The results showed significant difference between stress levels and between ecotypes for all studied traits (chla, chlb, chlt, carotenoied, Redusing sugars, total porotein and prolin amino acid). Stress caused to significantly decrease in level 0.01 of chla, chlb, chlt, carotenoied, Redusing sugars, total porotein and caused to significantly increase in level 0.01 of prolin amino acid. There were 3 factors that explained 82 percent in non stress condition and 83 percent of total variations in moderate stress condition and 81 percent of total variations in severe stress condition. Cluster analysis (Ward) was used to categorize ecotypes based on biochemical traits. This study showed that the in tolerance of red bean plant to drought stress was most likely due to chlorophyll degradation, reduction in sugars and protein reduction. As a result, these biochemical changes have made the plant susceptible to drought stress.