Abstract:In the past, the studies on the ecological carrying capacity were made only from an aspect of single factor, but the impact on the system carrying capacity of the integrated benefit of ecosystem was usually ignored. In the article, the carrying capacity of wetland ecosystem was studied in many ways, including water resources, land resources, water environment, biological resources, and so on. Using the grade evaluation method, the evaluation indexes and the carrying model were established, which were applied respectively on the evaluation of ecology elasticity, resources and environment bearing capacity, and carrying-pressing in the marsh wetland ecosystem. The method of analytic hierarchy process(AHP) based on real coded accelerating genetic algorithm was used to determine the weights，and the rank weights and the results of the compute had the characters of good stability and high precision. The method was used to evaluate synthetically the wetland ecological carrying capacity in Sanjiang Plain. The results showed that ecology system can be divided into medium stable situation, an upper carrying capacity and middle-low intensity region for the most part of the whole Sanjiang Plain. As a result, the ecological carrying capacity was high and the population pressure was low in the Sanjiang Plain. In order to improve the ecological carrying capacity, some measures should be taken to improve the wetland ecological environment and the utilization efficiency of water resource.