Abstract: In this study, Analytic Hierarchy Process (AHP) was used to confirm the hierarchical structure of composite grade evaluation system in marine oil spill sensitive area.The second level indexes of the system were marked as scores based on environmental sensitivity index (ESI) principal from National Oceanic and Atmospheric Administration (NOAA).The model of composite grade evaluation on marine oil spill sensitive area was established and the index weight was acquired by the combination of Delphi Method and AHP.Also, the spatial data corresponded with the second level index was coded with dynamic grid, according to spatial resolution, aided by GIS.Based on the mark obtained through coded single index layer, the composite evaluation grid graph was dynamically generated, combining with index weight.This method reduced the difficulty in determining the coefficient of index weight, during the confirmation of multiple indexes.The composite grade evaluation of marine oil spill sensitive area is realized.Self-cleaning properties, coastline and fishery were top three indexes in second level, with a total weight of 0.47.The importance of organisms and habitats were highlighted.However, as subjective assessment was applied, the system is highly dependent on consulting experts.