Objective To obtain the environmental background data of Caofeidian industrial area by investigating Caofeidian industrial area at its early stage, in order to provide fundamental data for carrying out continuous environmental monitoring and research of environmental science . Methods According to the construction status of the industrial area, dock, steel factory and control plot were chosen as the sample point, the samples of air, soil and seawater were collected. The concentration of the SO2、 NOx、 TSP、 PM10 of air and 21 indexes of seawater, such as temperature、 DO、 Cu et al and 8 indexes of soil, such as Cd、 Pb et al were determined . Assessment of the sample points and the whole industrial area were carried out by calculating the sample index and the integrated environmental quality index. Results All the contents of air pollutants in the sample points as well as the whole industrial area were lower than those of the related standards, and quality of the air was class Ⅰ, which belonged to cleaning air. The integrated environmental index of the surface seawater was 0.906, and the quality of surface seawater was better, the concentration of As beyond the standard with the sample index of 2.500; The integrated environmental index of the deep seawater was 0.779, and the quality of surface seawater was better, the concentration of Ni beyond the standard with the sample index of 1.904; The integrated environmental index of the seawater in the control plot was 0.107, and quality of seawater was clean; The integrated environmental index of the whole seawater of the industrial area was 0.502, and quality of the seawater was clean. The concentrations of 8 kinds of heavy metals in five sample points as well as the whole area were lower than the background values of related standards. The integrated environmental quality index of the whole area was 0.76, and the environmental quality of the area was at the verge of cleanliness. Conclusion The environmental quality of air and soil was clean in the caofeidian industrial area, and the environmental quality of the seawater is better. The total environmental quality of the whole industrial area is at the verge of cleanliness.