Environmental impact assessment(EIA)is the process of making a comprehensive assessment and prediction of the possible environmental impact of a project before planning,construction and development.As an important part of environmental impact assessment,environmental monitoring undertakes the responsibilities of data collection,information monitoring and evaluation,and plays a key role in the accuracy and credibility of the evaluation results.This paper focused on the application of environmental monitoring in environmental impact assessment,discussed the implementation methods of environmental monitoring in environmental impact assessment around the basic indicators of environmental impact assessment,and put forward corresponding optimization safeguard measures to improve the efficiency of environmental impact assessment,so as to provide more effective support for environmental protection and sustainable development.