Abstract: There are three types of lithologies such as carbonate rock, clastic rock and mixtite in Huangguamao area of Qaidam basin and conventional logging curves can’t be used to effectively identify the lithologies because the reservoirs in the study area are very thin. By using lithoScanner logging (LS) and imaging logging (FMI), mineral compositions and structures of the rocks can be identified, and then the reservoir rock type can be determined. Based on the well core, LS logging, FMI logging and comprehensive calibration of conventional logging, this paper identifies four categories of sedimentary microfacies and summarizes the corresponding logging characteristics of different microfacies. Firstly, for alga mat, LS logging shows that the calcite content of the alga mat is generally more than 80%, FMI logging is characterized by highlight and disorder or flocculent reflections and the conventional logging curve has the characteristics of ultra-low GR and low SP. For calcareous dolomitic flat, LS logging shows that its carbonate mineral content is more than 50%, FMI logging indicates that it is a weak-strong layer, while the conventional logging exhibits low GR, low SP and medium-high resistivity. For sand flat, LS logging shows that its felsic mineral content is higher than 50%, FMI logging indicates it has a blocky structure and the conventional logging exhibits a feature of medium-low GR and medium-low resistivity. The mineral compositions of marlstone (dolomite) flat are very complex, sandstone and marl are interbedded with each other, for this microfacies, a serious toothed LS logging curve is noted, FMI logging shows a strong stratification and the toothed conventional logging curve exhibits a feature of medium-high GR. Based on the logging facies analysis, detailed characterization is carried out for the spatial distribution of the sedimentary microfacies and the study results can be a guidance for the determination of the effective reservoir distribution in the area