Abstract: We examined the dissolved inorganic carbon (DIC) content, ion content, and soil physi-cal and chemical properties in Dagu River and Yanghe River estuary wetland of Jiaozhou Bay. Soil samples were collected by stratified sampling in the mudflat paralleled to the coastal zone and the river flat perpendicular to the coastal zone. Duncan method and Pearson correlation analysis were used to investigate the characteristics of soil DIC distribution and its driving factors. The results showed that the scouring action of water bodies led to the lowest content of soil DIC in the river estuary of mudflat, which showed an increasing trend with the increases of distance from the estuary. In river flat, the soil DIC content first decreased and then increased with the distance from the sea, which was influenced by human activities. Invasion of Spartina alterniflora significantly decreased soil DIC content, with its root transformation being the main reason for such decreases. The farming activities changed the environmental factors of aquaculture pond, and then changed the distribution of soil DIC. The surface soil of the pond had higher DIC content than that of the mudflat, while the other soil layers had lower DIC content than that of the mudflat. Soil DIC content was significantly positively correlated with soil salt content and total inorganic carbon content, and negatively correlated with soil pH.