Abstract: The distinguishing of oil, gas and water intervals is a basic task of petroleum exploration and exploitation. Geochemical methods play important roles in solving this task. In this paper, new advances of this study were shown based on a case study in Luxi area of central Junggar basin. It was found that the identification in different areas can not be settled in one rule. This is due to the geological and geochemical differences in reservoir rock. Two new geochemical indices are employed. They are organic geochemical index of grains containing oil inclusions (GOI) and inorganic geochemical index of Mn content of reservoir diagenetic calcite. From oil interval to oil?water mixed interval, to water interval, and to dry interval, these parameters have fairly good varying trend. The maximum GOI values range from >11% to 7%~11%, to 6%~7% and to <6%, and Mn content (MnO, wt%) ranges from >2.5% to 2.0%~2.5%, to 1.5%~2.0% and to <1.0%. As to the identification of gas (condensate) interval and heavy oil interval, it can be solved by biomarkers’geochemical parameters. It is shown that gas interval is characterized by the distribution of C202.0). The heavy oil reservoir is typically characterized by 25?norhopanes/html>