Investigation of the energy spectrum and GC/MSD for two pieces of calcilutites from the Sebei Well 1 in Qaidam Basin indicates that they are of obvious remaining bone of bacterium in these samples and there are the microbial characteristic biomarkers(aqualane and 2, 6, 10, 15, 19-pentanethyl-eicosane). For there are some bacterium-germs in the sedimentary rock of the Sebei well 1. The degradation of bacterium-germs has greatly changed the characteristic of distribution of the regular biomarkers: the alkane of the low-evolutionary rocks has been degraded firstly and represent the characteristic of OEP2>>OEP1, the ratio of C29ββ/(ββ+αα)and Σ8, 14-secohopane /Σhopane is unusually higher than the normal evolutionary samples in hydrothermal stage. These parameters may judge low-evolutionary sedimentary organic matter whether is degraded or not by bacterium-germ, at the same time they can indirectly judge whether it is biogas or not.
