The main problems of planning environment impact assessment are to deal with properly the relation between self-assessment and third party assessment,the time of starting PEA,alternative and public participation etc.

At the same time, the concept and function of alternative, PEIA methodology and the role of public participation are all elementarily discussed.

According to Law ofthe People's Republic of China on Environmental Impact Assessment, plans environmentalimpact assessment is a formal, synthetic and systematic process to appraisal theenvironmental impacts of plans and its alternatives.

Hierarchical comparison of alternatives in water transfer project;

Based on the theoretical research and the practical experience of environmental impact assessment at home and abroad, the paper discusses the meaning of alternatives, the definition, screening and analysis of alternatives for planning environmental impact assessment, and also the function of public participation in the process of the definition and the screening.

The paper discusses the meaning and action of alternatives,analyzes the importance of urban transportation plan EIA,and then,discusses the definition and analysis of alternatives urban transportation plan EIA,and also the function of public participation in the process of the definition.

During tendering for the water intake works for Zhangzhou Houshi Power Plant, the Second Engineering Company of the Fourth Harbour Engineering Bureau under CHEC and China Communications the Fourth Investigation ＆Design Institute for Navigational Engineering jointly made an alternative proposal to substitute for the original one, which was finally accepted as the formal construction scheme.

During the tendering for the water intake works for Zhangzhou Houshi Power Plant,the Second Company of CHEC-Fourth Navigational Engineering Bureau and Fourth Design Institute of Navigational Engineering jointly made an alternative proposal to substitute for the original design porposal.