The invention discloses a device for washing a rough surface of a precast concrete member. The device comprises an operation control console, a member rotary supporting platform, a waste water and waste residue collecting tank, a washing vehicle, a rail vehicle and a lower rail. The operation control console is arranged at a position where the operation of washing equipment can be observed conveniently and does not influence the inlet and outlet requirements of the member to be washed. The member rotary supporting platform is located at the center of the waste water and waste residue collecting tank, the lower end of the member rotary supporting platform is positioned in the waste water and waste residue collecting tank, and the upper end of the member rotary supporting platform is higherthan the outer edge of the waste water and waste residue collecting tank. One side or the two sides of the waste water and waste residue collecting tank is/are provided with the lower rail, the rail vehicle can walk along the lower rail, the upper side of the rail vehicle is provided with a washing vehicle rail, and the washing vehicle can walk along the washing vehicle rail. The problem that a worker directly uses a high-pressure water gun to wash the rough surface of the member is solved, the operation risk of splashing is reduced, the operation environment of the operator is improved, and the washing efficiency is improved.