The utility model discloses a special -shaped manual hole digging pile dado internal stay of adjustable dimension, the internal stay is the cuboid structure to have three group's arriss, first group arris is four straight section orientation subassemblies, and second group arris is four stake footpath orientation subassemblies, and third group arris is four stands, insert a straight section orientation tubule in two ports of straight section orientation bassoon in the straight section orientation subassembly respectively, the bassoon of straight section orientation is pegged graft fixedly through a first bolt and straight section orientation tubule respectively, insert directly orientation tubule of a stake in two ports of stake footpath orientation subassembly king -pile footpath orientation bassoon respectively, the orientation bassoon of stake footpath is pegged graft fixedly through a second bolt and a footpath orientation tubule respectively. The utility model discloses can be first through adjusting, the connecting length of the grafting position of two bolts and double -screw bolt adjusts the length of straight section orientation subassembly and four stake footpath orientation subassemblies to the size of adjustment cuboid structure is so that support the special -shaped manual hole digging pile of different straight segment length and different stake footpaths size.