The invention discloses a borehole sand-washing string, which is applied to oil field and oil well construction. An annular sand-washing base is fixed on the inner wall of the lower end of an oil string; an annular salvage base is fixed on the inner wall of the upper end of the oil string; a sand-washing device consists of a guide nozzle, a connecting cylinder, a rubber cylinder and a pressing cap; a conical face is arranged between a big cylinder at the upper end of the guide nozzle and a small cylinder at the lower end of the guide nozzle; the connecting cylinder is connected with the upper end of the guide nozzle; the pressing cap is fixed in a central screw hole of the connecting cylinder; and the annular ring body-shaped rubber cylinder is sleeved on the small cylinder at the lower end of the pressing cap. The borehole sand-washing string has the effects that: when positive circulation sand washing cannot be performed, the oil string is not required to be pulled out to be replaced with other tools, and sand-washing construction can be finished by directly throwing the oil string into the sand-washing device; and after sand washing is finished, the sand-washing device can be fished out without pulling out the oil string, and other construction can be performed by using the oil string.