In order to analyze and evaluate the suitability of the sites selected for oil and gas exploration support construction in Northern South China Sea, a progressive hierarchical structure model which includes 12 second-level evaluation criteria is established based on the principle of analytic hierarchy process (AHP) and the extensive studies of the characteristics of candidate areas and by taking the factors such as natural environment, development environment, infrastructure and investment, and so on as the first-level evaluation criteria. The validity and reliability of this model are then verified by using the Yongxing Island, the Zhaoshu Island and the Jinqing Island as candidate areas. The results from the AHP analysis have showed that the overall advantage and disadvantage indexes of the three candidate areas are 0.587 1, 0.212 1 and 0.200 8 respectively and the consistency ratio CR of the AHP model is 0.020 3. It is therefore concluded that the model established based on the principle of AHP and by analyzing and screening the site selection factors affecting the oil and gas exploration support constructions in the offshore areas can be used to evaluate quantitatively the suitability of the sites selected for the oil and gas exploration support constructions in Northern South China Sea.