Basing on the statistics results of environmental monitoring data source collected from 1998 to 2010 in the oil and gasjields which have been exploring and exploiting in the Cuu Long basin, the environmental status in sediment were expressed in space and time via three elements: (1) distribution of the particle size, (2) levels of pollutants in sediment including 07 heavy metals and some organic compounds 'specific for oil and gas industry and (3) the parameters of macro-benthos community. The results show that at most of sampling stations in the surveys, sediment environments are not significant change. However, the partial contamination of Total Hydrocarbon Contain (THC), PolyAromatic Hydrocarbon 2-6 rings (P AH-6 rings) and Barium at higher rate than the baseline value from a few dozen to several hundred times were also recorded at a few stations in the 250m-ring and 500m-ring. In consequence, the decreasing of number of species and diversity index were also recorded at these stations. In the case of continuous discharging, these negative effects was lightly accumulated increased over time
in the case of stopped discharging, the pollution was declined sharply, especially in THC.