In this study, one surface floating longline and two underwater floating breeding facilities were set up in the vicinty waters of Taipower wind measurement tower, in the offshore waters of western Changhua, on April 30 and June 1, 2019, for breeding the oysters, Pinctada margaritifera, mussels. Their growth and mortality data were collected on March 20, April 30, June 1, July 30, September 6 and October 4, 2019. The shellfish growth data were obtained only on July 30, summer, due to the offshore breeding facilities were destroied and the theft of shellfish. During the summer, the shell length of offshore breeding oysters did not increase significantly, with a mortality rate of 14.6%, which is much lower than that of traditional intertidal oyster culture. The average shell length of Pinctada margaritifera was decrease due to the death of the larger shells, and its mortality rate was 82.9%. The average shell length of mussels increased about 8.5mm, and the mortality rate was 47.1%. A large number of Elagatis bipinnulata juveniles have gathered near the offshore aquaculture facility, indicating that this aquaculture facility also functions as a reef. This study also conducted marine environmental surveys including phosphate, silicate, nitrate, ammonia and chlorophyll concentrations.