Abstract: The type and maturity of organic matter in deposit are obtained by using rock pyrolysis，extracting and quantification of chloroform bitumen “A” and its group components and determination of the vitrinite reflectance so as to analyze the role of the organic matter in the process of uranium mineralization.The results showed that the type of organic matter in 373 uranium deposit isⅡ₂，which mainly comes from marine plankton，microorganisms and terrestrial plants.The organic matter owns a low maturity and lies in the early stage of immature and low mature.Compared with the surrounding rock，organic matter has experienced the relatively high palaeogeothermal on account of the effects of hydrothermal and fault on ore-body.The large amount of humic acid that are determined by the type of organic matter and maturity are produced in the evolution process of organic matter and are stored in strata.The content of chloroform bitumen “A” of organic matter in the deposit is(0.47~10.42)×10^-6，asphaltene is the main composition of chloroform bitumen “A” of the organic matter.Chloroform bitumen “A” has good correlation with the asphaltene content and uranium content.The comprehensive research results showed that absorption，complexation and reduction are the main function of organic matter in the process of 373 uranium mineralization.

Key words: Uranium mineralization, Organic matter, Maturity, Chloroform bitumen “A”