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.

Objective To establish neutral red uptake test of 3T3 in vitro to detect phototoxicity of chemicals and study the in vitro 3T3 NUR as an alternative method instead of animal skin phototoxicity test.

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.