The invention belongs to the field of municipal tunnel design, and particularly relates to a supporting manner for a fully-sandy bed dry dock slope. The supporting manner is characterized in that dry dock diaphragm walls are used for isolating a foundation pit in a dry dock from outside water; a grading sloping manner is adopted in the dry dock slope; a formworking reinforced concrete protective face is adopted on the slope face of the dry dock slope; a water filter sand ridge is arranged at the position, on each grade of sloping platform, of the slope face of the dry dock slope; a drainage ditch is arranged at the position, on each grade of sloping platform, of the slope foot of the dry dock slope; one end of each PVC pipe is inserted into the corresponding water filter sand ridge, and the other end of each PVC pipe is arranged outside the corresponding water filter sand ridge; and perforated steel pipes penetrate the formworking reinforced concrete protective face to the fixed to the dry dock slope. The adopted dry dock diaphragm walls are good in waterproof effect and high in adaptability to bed deformation; and the slope protection manner of formworking reinforced concrete, the perforated steel pipes and the water filter sand ridges is adopted, so that the construction quality is good, high integrity is achieved, and the supporting manner is quite suitable for protection of the fully-sandy bed slope.