Abstract: We investigated the habitat (Dacheng Bay, Raoping County), gonadal development and seasonal change of condition factor of Chinese sanguin (Hiatula chinensis). The results show that H.chinensis is vertically distributedfrom the low intertidal zone to the 5 m below the surface water of Dacheng Bay. The range of water temperature is 16.3~29.0 ℃ and that of salinity is 18.5~33.7; the sediment is mainly the fine sand with granule diameter of 63~250 m. The condition factor of H.chinensis ranges from 5.74% to 21.66%. According to the changing rule of condition factor and the gonad development, H.chinensis has one reproductive period per year, from July to September, andmatured gonad can be found in the one-year old individuals.