The invention discloses a flexible shaft assembly of a cattle abomasum left displacement surgical reduction apparatus. The flexible shaft assembly comprises a transmission flexible shaft and a propelling unit, wherein the transmission flexible shaft comprises connecting pieces, a flexible shaft core assembly, a flexible shaft pipe assembly, a power input head and a power output key head; the two ends of the flexible shaft pipe assembly are both connected with one connecting piece, and the connecting pieces are supported on the flexible shaft core assembly through bearings; the power input headis in matched connection with the tail part of the flexible shaft core assembly; the power output key head is in matched connection with the head part of the flexible shaft core assembly; the connecting pieces comprise the pipe tail connecting piece and the pipe head connecting piece; the propelling unit comprises a guide pipe, a rotating shaft, a guide shaft, a needle storage bin and a reductionneedle with a wire binding hole, the needle storage bin is fixedly connected to the head of the guide pipe, the reduction needle is arranged in the needle storage bin, the tail part of the reductionneedle is inserted into the head of the guide shaft and fixedly connected with the guide shaft, supporting bearings sleeve the two ends of the rotating shaft, and the rotating shaft and the supportingbearings are embedded into the guide pipe; the transmission flexible shaft can be flexibly bent, the compression on internal organs is reduced, the reduction needle can be repeatedly used, and the operation time is shortened.