Abstract: arine food web plays an important role in marine ecological system. Compound-specific isotope analysis (CSIA) is a new approach in this field. It provides more abundant and precise information in the studies of marine food web compared to stable isotope analysis for bulks and tissues. Stable isotopic characteristics of fatty acid and amino acid can reveal trophic structures, matter and energy flow processes of marine food webs in detail. Compound -specific isotope analysis has displayed its applicability in many fields, particularly in the study of special food web under extreme environment, such as vent system. Although there are some limitations in utilization, the new technique is very promising in future studies.