Lake Ge Hu, which is a shallow lake (average depth 1.25 meters)with a area of 137.82 square kilometers, locates in the southwest of Jiangsu Provin-ce. The lake is rich in submerged plants (over 86% is covered). Since 1984, therehas been developed pen fishculture in the lake, the yield of pen fishculture was upto 4664 tones in 1988. The evaluation of water trophic state, scale of development ofpen fishculture and feeding conditions in the lake mainly based on the surveys du-ring 1985--1989. The result indicates that the lake belongs to mesotrophic type(early). Although the eutrophication is progressing after yet, the process is stillslower than that in other similar shallow lakes. Accordingly,the proposation of samemeassures for lagging the lake eutrephication is based on the analysis.