Offshore wind power is one of the important developing renew energy in Taiwan. The potential wind farms are distributed in the waters of western Taiwan. The zone is the important coastal fishing ground in Taiwan. We investigated the marine environmental factors, the bottom trawl study, and the fishery survey to understand the effects of the marine environment and fishery resources with the installation of the offshore wind turbines in Taiwan Strait. The monsoon and current affected the marine environment in western water of Taiwan. China Costal Current brought the water mass which was low temperature and low salinity, and carried the rich nutrients in water. In spring, seawater temperature became higher. Phytoplankton absorbed the nutrients, and the concentration of chlorophyll a increased. The richness of zooplanktons increased in summer, and chlorophyll a decreased. The relation of trophic levels is interrelated to the food. It is exceeded 130 kinds of the fishing species including fish, crustacean, and cephalopod etc. in Changhua offshore. They were common species, and fished all year. Above the result, it showed high biodiversity occurred in the sea of Changhua offshore wind farms by the monsoon and seasonal currents.