Abstract: Carbon and nitrogen stable isotope composition (δ13C,δ15N) of woody plants are effective indicators for monitoring vegetation and environmental change. An investigation of carbon and nitrogen isotope compositions was conducted in the Yellow River Delta Wetland. It is found that even the values of stable carbon and nitrogen isotopes have wide distribution ranges in plants, but C3 plants are dominant. Nitrogen isotopes of plants have no correlation with carbon. Stable carbon and nitrogen isotope values in the soils exhibit a weak negative correlation, suggesting two main sources of soils in this area. Corg/N ratios of soils have an apparent difference. In most of the area, the ratio exceeds 12, indicating that the main sources of soil organic matters are from the drainage basin.