Abstract: Abstract: Drainage ditches, which are abundant in the southern river network area, provide drainage services for farmland and are also valuable resources for reducing agricultural pollutants as well as providing habitats for wildlife. It is really a precious natural resource. However, since ditches also occupy part of the land resources, and hindered the mechanization of operations. There is a certain contradiction between mechanical operation and the development of modern agriculture. How to balance various needs in rural ecological construction and protection has become an urgent scientific problem to be solved. Based on a typical case, according to the different emphasis of environmental protection and land increase, this paper analyzed the optimization of ditches/ponds protection while calculating the benefit change in different scenarios, and considered some difficult-to-quantify factors to explore the best transformation mode of the ditches and ponds. The existing ditches/ponds area in this study is 0.82 hm2, accounting for 14.3% of the farmland, of which the proportions of ponds, branch ditches and farms are 28%, 60% and 12%, respectively. The results of economic analysis show that according to the current land lease price, the economic benefits of reducing the area of the ditches/ponds and increasing the land use are higher than those of the ditches and ponds in terms of pollutant removal and ecological pest control. In combination with other factors that are difficult to quantify, this paper recommends that the branch ditches, which are distributed along the edges of the plots and have large area, should be reserved in order to maintain the original drainage and ecological environment functions while ensuring less impact on the field mechanical operations. For densely distributed and small size ditches, it is recommended to use drainage tube instead, which can minimize the impact on the field mechanization operation and reduce the impact on the ecological environment; For those larger and unevenly distributed ponds, considering their small population and limited impact on farmland drainage, can be reclaimed for reclamation on the basis of well-drained drainage facilities. For the study area, the above proposal will reduce the total area of the ponds from 8 020 m2 to 4 818 m2, reduce the area ratio of farmland from 14.3% to 8.6%, and the comprehensive economic benefit ratio can be increased from the current 5 217 to 6 740 RMB; however, the pollutants removal and pest control role will be reduced from the current 5 217 to 3 134 RMB, while the land rental income increases to 3 606 RMB. Therefore, simply from an economic point of view, the benefits of increasing land area should be higher than the economic benefits of reduced pollutant reduction and pest control. If the land proceeds increase in the future, the added value of land area will be more significant. Taking into account some difficult factors such as the provision of habitats and cultural landscape values, the protection and transformation of ditch pond systems in the future will also need to coordinate the demands and efforts of different departments.