There is a growing concern on the environmental impacts resulted from construction activities. Environmental Assessment (EA) has been advocated as an effective tool in reviewing, monitoring, checking and evaluating environmental performance for the construction industry. Although there is a plethora of environmental assessment tools, most of them are not designed for construction. This paper proposes a system named as "Green Construction Assessment" (GCA) for construction. Two types of environmental indicators are included; namely, Management Performance Indicators (MPIs) and Operational Performance Indicators (OPIs). Using a multi-criteria decision system, the Non-structural Fuzzy Decision Support System (NSFDSS), the weights for each criterion and sub-factors are developed, producing a yardstick for assessing the environmental performance at the construction stage.