Abstract: In this study the main purpose is to study on some biological factors of a deciduous tree species Callistemon citrinus in polluted and high temperature condition in South of Iran. The location was selected because of high rate of industrial pollution that is caused by petrochemical companies. Callistemon citrinus, family Mirtaceae, is a kind of evergreen tree with alternate, linear leaf. The type and margin of leaves are simple and entire, round brown fruits with hard or dry cover and red flowers. The common name of C. citrinus is red bottlebrush that is describe its flowers shape. The concentrations of chlorophyll A, B total chlorophyll, carotenoieed, soluble sugar, proline and morphological effects were examined in the leaves of tree species, growing in polluted area as compare to unpolluted condition. In the polluted regions higher concentrations of soluble carbohydrate, proline, chlorophyll A, B, carotenoieed were observed in comparison with trees in the unpolluted regions. The morphological characters affected by stress of pollution. Characters such as leaf area, length and breadth of blade, showed decrease.