The invention relates to a level draining system for mud texture soft soil foundation and draining construction method thereof. drainage ditches are arranged around the mud texture soft soil foundation; a layer of silver sand are laid on the mud texture soft soil foundation; vertical plastic drain bars are inserted with intervals from the silver sand into the mud texture soft soil foundation; theupper part of the drain bar is bent to the level surface of the silver sand; level plastic drain bares are fixed on the bent parts of the vertical plastic drain bars; the level plastic drain bar comprises a latitudinal level plastic drain sub-bar and at least two longitudinal level plastic drain sub-bars; the latitudinal level plastic drain sub-bar is arranged along the length direction of the foundation pressing against the bent part of the level plastic drain bare with the two ends extending to the drainage ditch around the mud texture soft soil foundation; the longitudinal level plastic drain sub-bar is parallel with the foundation length direction and presses against the latitudinal level plastic sub-bar. The invention solves the problems of high complexity, high cost and no guaranteeto construction progress existing in the mud texture soft soil foundation draining construction.