The interaction between engineering construction and geo-environment is one of the core problems which have to be dealt with for the sustainable development of the society. It is also the key relationship underlying the main scientific studies environment geology engineering (EGE) has to undertake. System analysis are the scientific tools with which the relationship can be delved into; whereas geo-engineering, which stresses engineering and geo-environment as a whole, is the foundation upon which the relationship can be practised. The technique system of data acquring and processing, experimenting and simulating, monitoring and forecasting, and comprehensive information system are supporting technology for the analysis of their interactive mechanism. The paper finally points out that macro-coordination and micro-control are conductive to reach the harmonization between engineering construction and geo-environment.