Macro Benthos of Amirkelayeh wetland (located in north of Iran, with vastness of more 1230 ha) surveyed monthly (from January to December 2003). For this purpose, from 6 sampling station was sampled by Grab. According to this survey, 17 groups of Macro Benthos recognized include: Odonata, Hirudina, Trichoptera, Nematodes, Planorbidae, Naididae, Caenidae, Noucoridae, Ceratopognidae, Chinodoridae, Physidae, Chaoborina, Culicidae, Gammaridae, Tubificidae, Limnaeidae and Chironomidae. The highest abundance of Macro Benthos was Gammaridae and least abundance was Noucoridae. The highest biomass was limnaeidae and was 227n/m2. Meanwhile, in between of different seasons, highest abundance was spring with average 361n/m2 and least abundance was summer season with average 120n/m2. Also, between of different months, highest abundance of Macro Benthos was June with average 550n/m2, and the least abundance was October with 81n/m2. The average Biomass in during years was 3.53gr/m2. The highest biomass was in autumn season with 5. 57 gr/m2 and the least Biomass were in summer season with average 0.67 gr/m2 .The highest Biomass of Macro Benthos was November with average 8.26 g/m2 and least Biomass was October with average 0.39 gr/m2.The highest abundance and Biomass of Macro Benthos was station 1 with 294 u/m2 and7 gr/m2 and least abundance and Biomass was station 6 with116 n/m 2 and 102gr/m2. According to survey feeding by fishes, type of bottom, water temperature and rate of organic mater, is most important factor that effect on population change and Biomass of Macro Benthos in stations, seasons and months of Amirkelayeh wetland.