Abstract: Sealed incubating experiment about the sediment of seawater cage aquaculture in Dapeng'ao Bay was conducted in May 2005, and in-situ investigation of the environmental factors was also made, these factors include water temperature, DO, BOD5, COD and pH. The result indicated a significant SOD appeared in the testing area and the values of SOD in cage area were higher than that in the contrast area. Nonlinear variations were determined between SOD and incubation time, meanwhile, preferable pertinences between SOD and DO, COD, BOD5 and pH were determined.