The invention discloses a dredging device of a solid-liquid mixture conveying pipeline bend, a bend feeding valve is arranged between a feeding pipe and the bend, a bend discharging valve is arranged between a discharging pipe and the bend; a feeding dredging pipe, a feeding dredging valve and a high-pressure gas-water pipe which are communicated with the bend and coaxial with the feeding pipe are arranged at the bending part of the bend, and the feeding dredging valve is movably, tightly and serially connected between the feeding dredging pipe and the high-pressure gas-water pipe; a discharging dredging pipe, a discharging dredging valve and a high-pressure gas-water pipe which are communicated with the bend and coaxial with the discharging pipe are arranged at the bending part of the bend, and the discharging dredging valve is movably, tightly and serially connected between the discharging dredging pipe and the high-pressure gas-water pipe. Compressed air or high-pressure water can be introduced into the high-pressure gas-water pipe, and the bend blocking can be dredged by opening the corresponding dredging pipeline valve, and the bend blocking can be also manually dredged afterthe dredging pipeline valve is detached. The invention has low cost, convenient operation, rapid dredging and remarkable effect.