Abstract: We measured the Vibrio density in aquaculture water of Haliotis discus hannai by cultivation method, and investigated the main environmental factors including temperature, dissolved oxygen, potential of hydrogen, salinity, redox potential, nitrite, nitrate, ammonium and phosphate, so as to study the relationship between Vibrio quantity and main environmental factors. The results show that Vibrio density throughout the whole year varied from 0.2102 cfumL-1 to 6.03103 cfumL-1(average 1.7103 cfumL-1). When the temperature was less than or equal to 25 ℃, the Vibrio density had no correlation with any environmental factor; when the temperature washigher than 25 ℃, the Vibrio density had significant correlation with temperature (P0.05), redox potential (P0.01), nitrate (P0.01) and ammonium (P0.01), but had no correlation with the others.