Estuary is an ecosystem that is vulnerable to pollution and community activities in Cimadur Estuary for daily activities without consciousness which can pollute the environment if not used wisely. Pollution in Cimadur river has occurred over the past few years, the research about estuary boundary based on salinity using several variables such as surface currents, tides, and rainfall. This research aims to know the estuaries boundary of Cimadur based on water surface salinity which is adjusted between the measurements of salinity in the field and the processing of satellite imagery. The research is also to analyze the relationship of each variable that current sea levels, tide and rainfall as the variables that affect the levels of surface salinity to the suitability of fish larvae habitat. This research uses quantitative methods that compare the data and analyze the results of remote sensing imagery. Data are presented as the result of a measurement statistics directly or indirectly, so it can be presented in the descriptive form. Map of results is a salinity distribution to form an estuary boundary and distribution of fish larvae catching location on the Cimadur estuary.