This paper attempts to examine the changes in surface water environment and community based coastal resources management activities in the Tam Giang Lagoon, Central Vietnam. The results show that the lagoon’s surface water has been polluted. BOD5, COD and nutrient concentration have increased in the lagoon’s surface water environment. It proved that there was a present of organic substances. Due to the globalization of seafood products and changes in lagoon’s water quality by aquaculture development; the local government has.