Abstract: Wetland resources have important values on biodiversity protection in Liaoning coastal economic belt.Based on the principles of scientific approach,representativeness and practicality,four indexes of biodiversity assessment were proposed,i.e.species richness,diversity of ecosystem types,species endemism and invasion extent of external species.A biodiversity assessment index system on the coastal wetland was established,and the biodiversity in the coastal wetland was assessed.The results show that the biodiversities of 6 coastal cities and 4 coastal nature reserves in Liaoning province are rich.This study would help to biodiversity protection in Liaoning coastal economic belt development and decision-making.