Bacteria numbers in water of coastal shellfish culture area around Qingdao were examined in April, August and October 1998 respectively. The results showed that the total numbers of heterotrophic and coliform bacteria in waters of the area and the specific geographical area varied with seasons. The highest populations were recorded during summer, i.e. 1 0×10 4～4 5×10 6cell/ml and 3 0×10 0～2 4×10 3cell/100ml, and with average values of 1 61×10 5cell/ml and 1 24×10 2cell/100ml respectively. The second highest populations occurred in autumn, and the lowest were in spring. The numbers of coliform bacteria were relatively low in waters near the mouths of bays and open part of the shellfish culture area, while those in waters near the estuaries of big rivers, wharves, navigation routes or the area in front of downtown areas were much higher than other areas. Single index assessment of the environment quality of shellfish culture was made to indicate that the water sanitary quality in most of these areas are very good, however, some parts were serious polluted by the faeces of warm blood animals. These results provided theoretical reference for the programming and organizing of shellfish culture. Bacteria numbers in water of coastal shellfish culture area around Qingdao were examined in April, August and October 1998 respectively. The results showed that the total numbers of heterotrophic and coliform bacteria in waters of the area and the specific geographical area varied with seasons. The highest The populations were recorded during summer, ie, 1 × 10 4 to 4 5 × 10 6 cells / ml and 3 × 10 0 to 2 4 × 10 3 cells / 100 ml, and with the average values ​​of 61 × 10 5 cells / ml and 1 24 The numbers of coliform bacteria were relatively low in waters near the mouths of bays and open part of the shellfish culture area, while those in waters near the estuaries of big rivers, wharves, navigation routes or the area in front of downtown areas were much higher than other areas. Single index assessment of the environment quality of shellfish culture was made to indicate that the water san itary quality in most of these areas are very good, however, some parts were serious polluted by the faeces of warm blood animals. These results provide theoretical reference for the programming and organizing of shellfish culture.