The engineering activities can be divided into three levels:micro,meso and macro.Economists and ethicists have different views about how the three levels should be divided.Based on the definition by economists,this paper analyzes and elaborates on the three levels of micro,meso and macro and the their evolutions.Finally,the paper analyzes the interaction of the micro,meso and macro levels,pointing out we should pay attention to the research such issues as the embedded and beyond relationships of cross level,and the mechanism of upstream or downstream between different levels.