【Objective】 As an important component of the soil microorganisms, fungi play an important role in cycling nutrients, maintaining and building soil fertility and improving soil structure and so on. As a decomposer in the soil, fungi can effectively decompose various kinds of macromolecule materials and hard-to-decompose litters in the soil, promote nutrient uptake of plants, and be used as an indicator of ecosystem health. Carbon source utilization capacity of soil fungi reflects overall metabolic characteristics of the fungal communities. To explore relationships between soil fungal carbon source metabolism and succession of halophytic vegetation is an important step to elucidate variation of the ecosystem in internal structure and function. 【Method】 In the region of the Yellow River Delta, in line with the natural succession of the halophytic vegetation, sample plots of bare coastal tidal flats, flats covered with Tamarix chinensis and Angiospermae (highly salt-tolerant plant community), and flats of Imperata and A.venetum (mildly salt-tolerant plant community) were selected, three each, making up a total of 15 sample plots for soil sampling in the 0~20 cm and 20~40 cm soil layers. The soil samples were analyzed for physicochemical properties, and carbon source metabolic activity of soil fungi using the Biolog-FF microplate culture method, and further for characterization of the carbon metabolic activity of the soil fungi in the plots relative to halophytic vegetation. 【Result】 The Biolog-FF microplate tests show that in terms of average well color development in the 0~20 cm soil layer, the plots followed an order of Imperata > A. venetum > Tamarix chinensis > Angiospermae > Bare plot, while in terms of AWCD in the 20~40 cm soil layer, they did an order of Imperata> Angiospermae > Tamarix chinensis > A. venetum > Bare plot, which suggests that with the succession of the halophytic vegetation, carbon metabolism activity of the fungi in the soil increases significantly (P) and so was Shannon-Wiener index, richness index and Simpson index of the fungi. In all the sample plots, except for that under Angiospermae, all the three indices were higher in the 0~20 cm soil layer than the 20~40 cm one, which suggests that with the succession of halophytic vegetation going on positively, the fungi in the soil improve in diversity and abundance and in dominance of common species in the community. Correlation analysis of soil properties, fungal AWCD and fungal diversity shows that TN, AN, SOM, phosphatase and catalase significantly (P<0.05) promoted while soil salinity significantly (P<0.05) inhibited fungal metabolism of carbon sources. Principal component analysis shows that Fibric alcohol, ornithine and D-mannitol were the main carbon sources for fungal utilization in the 0~20 cm soil layer, whereas D-sorbitol , glycerol and L-aspartic acid were in the 20~40 cm soil layer, which suggests that saccharides, alcohols and acids are the main carbon sources that control carbon metabolism of the fungi in the soil. 【Conclusion】 As a whole, with the succession of the halophytic vegetation going on positively, the soil underneath declines gradually in salinization degree and improves in soil quality, and the fungal community in the soil is growing more and more stable in structure. All the findings about relationships between carbon source metabolism of soil fungi and succession of halophytic vegetation may lay down a theoretical foundation for the ecological restoration and utilization of the Yellow River Delta.