In order to master the farmland productivity and the middle-and-low-yielding fields distribution of Funan County and study the relative improvement measures to use, in this paper, making use of the Funan County’s text materials, such as the second time soil census and soil testing data, supported by GIS and computer technology, its cultivated land’s productive potentials were divided, and then, according to the grade standard of national low yield farmland type partition and improved and Funan County’s actual situations, the Funan County’s middle-and-low-yielding fields were divided by level 2 type system. The results showed that the farmlands’ productivity can be divided into five levels, and the middle-and-low-yielding fields could be divided into three types: drought irrigation type, stains waterlogged gleysols type and waterlogging drainage stains type. At the end of this paper, the targeted gain and soil improvement countermeasures and suggestions were put forward.