The invention relates to an assembled leakage-proof bottom plate of an upper ditch of a overlapped type ditch. A field balk is formed by the upper ditch through utilizing the movable closing of a cover plate; a bottom plate, namely a lower ditch top plate, is laid to a boss on a ditch wall at the top end of a lower ditch, and sticky bricklaying is not needed; a connecting crack in a bottom plate flowing end adopts a phenomenon that the upper part is narrow, the middle part is wide and the bottom ends are closely connected; a connecting crack in a ditch wall end adopts a phenomenon that the upper part is wide and the lower part is narrow, and anti-seize processing is performed; each of the connecting cracks are filled by a sealant or a swelling belt which is expanded when facing water; and a bottom plate edge pressing body which is bolted in the ditch wall is arranged at end parts of two ditch walls on the upper surface of the bottom plate. According to the packaged leakage-proof bottom plate disclosed by the invention, a drainage ditch and an irrigating ditch are replaced by the field balk, so that one place has three purposes, and massive valuable soil is saved; according to upper ditch irrigation, high-water-level water is not blocked, and according to the lower ditch flood drainage, the drop height is adequate; passengers and weeds are not fallen to a ditch path, so that the draining capacity and the irrigating capacity of the ditch drain, the moisture exhausting capacity and warming capacity of a farmland, and the fertilizer storing capacity of a plough land are greatly improved; irrigating the farmland below does not influence the drainage of the above farmland to the ditch, so that massive production labor is saved, massive flood fields are converted into good fields, and the purposes that the nation is rich and people are strong are promoted; and the packaged leakage-proof bottom plate has advanced advantages of scenery spot benefits to drive the tour industry of a country, convenient and time-saving in subsiding crack maintenance and the like.