The purpose of this experiment was to study the water quality of aquaculture area at Tai-Shi coast. From July 1999 to June 2001, water samples were collected 72 times at seven stations. Thier water temperature, salinity, pH, DO, suspended solid (SS), BOD, COD, ammonia-N, nitrite-N, nitrate-N and orthophosphate-P were analyzed. The results showed that water temperature and salinity varied with seasons and regions. The monthly average pH value was 7.74-8.65 at seven stations in three years, SS, 27.17-132.23 mg/L; DO concentration, 5.90-8.62 mg/L; BOD5, 0.50-12.5 mg/L; COD, 1.04-5.82 mg/L; ammonia-N, 0.03-1.54 mg/L; nitrite-N, 0.007-0.237 mg/L; nitrate-N, 0.04-1.25 mg/L; orthophosphate-P, 0.02-0.26 mg/L. The levels of these parameters in drain canal and old Ho-Wyu river station were higher than those in the other areas. The waters of Tai-Shi coast were up to the A grade, according to the criteria for marine enacted by the Department of Health. Thus, aquaculture was workable in the waters.