The article presents research results of socio-economic impacts, mainly on salt-marsh plants in Lap An lagoon from the application of methods in sociological investigation, field monitoring and GIS technology. The results determined 5 key socio-economic activities degrading the area, disposition, quanlity and components of salt-marsh plants in Lap An lagoon, which are activities of: 1/ Agricultural production
2/ Infrastructure building
3/ Inhabitant re-arrangement
4/ Leveling of mangrove swamp
and 5/ Other people's livehood. Due to socio-economic impacts, there are over 65 hectares of salt-marsh plants in Lap An lagoon disappeared, many times as large as the remaining area of salt-marsh plants in the lagoon.