Lake Ge Hu situated in the southwestern part of Jiangsu Province is a typical shallow lake. The lake with an area of 137.82 square kilometers is rich in submerged plants. The nutritive composition of aquatic plants in the lake are analyzed. The degree of like feeding on several species of submerged plants by herbivorous fishes is tested. The results indicated that Vallisneria spiralis,Hydrilla verticillata and Potamogeton crispus are likely fed by grass carp and bream. In order to promote the flourishing of high quality for aquatic plants,different transplanting ways have been carried out in Lake Ge Hu. Based upon investigation on productivity of Vallisneria apiralis an interval of 23 days between the two mowings is suitable. The technical measures for fish culture in mowing are presented. This paper gives some suggestions on how to develop pen fish farming in the lake. enclosure.