Vibrio unlnificus, a normal inhabitant in estuaries, is of great concern because it is a potent human pathogen causing septicemia, wound infection and gastrointestinal disease in Kum river, sampling was undertaken in five station from March, 26, 1993 to February, 22, 1994. Samples of 54 and 49 were collected from seawater and bottom deposit. The total detection rate of V. unlnificus was 11.7%. The detection rates of V. unlnificus in the seawater and the bottom deposit were 9.3% and 14.3% respectively. V. unlnificus was mainly detected in estuary water when temperature was above 23$^{circ}C$ and salinity was below 15%. We suppose that water when temperature, salinity, pH and COD affect growth of V. unlnificus.