As a major ecosystem type, wetland provides invaluable ecological services. Environmental pollution, especially Pesticide runoffs have to be paid more attention to keep wetlands healthy. This paper propose Methodology namely, deterministic approach for assessment of ecological risk of pesticides on shadegan wetland. Deterministic approach or risk quotient (RQ) was calculated using the water concentration and toxicant reference values of five pesticides (DDT, Aldrine, Dieldrin, Ametryn, Lindane) in shadegan wetland in 2010. The results of deterministic approach showed that the highest of RQ for insect larvae (Chironomus sp.) 4/3 µg/l, shirbot or large scaled barb (Barbus grypus) 1/06 µg/l, benni (Barbus sharpeyi) 0/9 µg/l, golden barb (Barbus luteus) 0/7µg/l relation to other studied groups of phytoplankton, zooplankton, vertebrates, insects and fishes are showed.Also the environment is exposed to Higher risk. It is recommended that proper countermeasures should be implemented to reduce the risks.