The effects of growth hormone (GH)in the seawater on Penaeus Chinensis postlarval were studied. The GH-treated groups higher growth (in body length) and survial rates than the control groups; and built up its resistance to the change of high salinity. In addition, the fine structure of the gills of the shrimp treated with 43‰ salinity seawater was observed by electron microscope, and the osmoregulatory mechanism was investigated. Treatment with GH to accelerate growth important measure as it can advance the date of postlarva and avoid shrimp disease in the high temperature season.