Abstract: In recent years, a lot of agroforestry systems have been developed in Lixiahe region, Jiangsu province. Economic, ecological and social profits have also been achieved by exploitation and uses of wetland resources. I n this paper, authors have used relationship analysis to investigate relations b etween microclimatic factors and the yield of wheat interplanted under forests w ith different densities. The results showed that the decrease of radiation was t he key factor that caused the decrease of wheat yield. A grey system model was d eveloped to predict interplanted wheat yield and determine appropriate stand den sity in agroforestry systems.