Currently,the main way to construct marine ranching and reform habitat is to build up underlying reefs,however the whole ocean water space can't be fully used in these aspects,such as generating upwelling of nutrient substance,bait field, spawning ground and biological chain,which do not maximize its efficiency.To solve this problem,based on sea conditions and biological characteristics in offshore waters in the East China Sea,a kind of upper-middle-class floating reef is developed that can cooperate with bottom reefs.Proceed from improving flow field and keeping volume unchanged,the flexible floating reef with four layers frame was designed,then its buoyancy force,gravity and capability of resisting waves were calibrated and calculated.The technical scheme of anchor system and the method of monitoring its applying effect underwater were determined.Three reefs were placed in marine ranching of Xiangshan Bay to test their practical effect.The test results show that the designed reef can effectively improve the regional flow field.It can keep tensile state in axial and has a tilt less than 20 degree in strong tidal current.The data from several investigations and video monitoring system show that the upper-middle-class flexible floating reefs can cooperate with the bottom reefs.Some fish appeared stably around after the floating reefs were placed for 2 months.The effect is satisfactory.