Vibrio vulnificus, a normal inhabitant in estuaries, is of great concern because it is a potent human pathogen causing septicemia, wound infection and gastrointestinal disease in susceptible hosts. To elucidate the distribution and environmental factors of V. vulnificus 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. vulnificus was 11.7%. The detection rates of V. vulniftcus in the seawater and the bottom deposit were 9.3% and 14.3% respectively. V. vulnificus was mainly detected in estuary water when temperature was above 23℃ and salinity was below 15‰. We suppose that water temperature, salinity, pH and COD affect growth of V. vulnificus.