The high level of community needs towards the fulfillment of the necessities of life increases the activity of the utilization of natural resources especially coastal and sea. Ihamahu Village has nine lagoons that have the potential to meet the needs of people because of the high productivity of lagoon ecosystems. The purpose of this research is to know and map the form and pattern of utilization conducted by Ihamahu Village society on lagoon ecosystem. The research method was conducted using questionnaire directly in Ihamahu Village through FGD (Focus Group Discussion) activity. Analysis data of FGD results will be poured in the form of maps and patterns of community utilization Ihamahu Village in the lagoon ecosystem. The results of this research show that the utilization of lagoon ecosystem is catching fish, bameti and garbage disposal. All three activities are undertaken throughout the year with less intentity especially in fishing activities and bameti occur in the west season. The high number of fishing activities using redi fishing equipment that is not environmentally friendly and has been prohibited by the government resulted in a decline in the number and size of the catch. For that form and pattern of utilization that has been done so far needs to be regulated so as to produce sustainable lagoon ecosystem management.