The invention relates to a yarn hanging rod sliding groove locking device. The yarn hanging rod sliding groove locking device comprises a sliding groove body, a T-shaped rod inserted in the sliding groove body in a matched manner, and a locking piece. The T-shaped rod comprises a sliding block and a hanging rod arranged in the middle of the sliding block. A square through hole is formed in the middle of the sliding block. A threaded through hole is formed in the middle of the side wall of the sliding block. The hanging rod is welded to the middle of the sliding block, and a cavity is formed in the position, corresponding to the threaded through hole, on the side close to the hanging rod. The locking piece comprises a locking rod arranged in the cavity and a pair of ejecting blocks. One end of the locking rod is arranged in the cavity, the other end of the locking rod is inserted in the threaded through hole in a matched manner and is arranged in the square through hole. A pair of screwing blocks inserted in through grooves in a matched manner is arranged on one side in the cavity. The yarn hanging rod sliding groove locking device has the beneficial effects that the sliding groove body and the sliding block which are matched in pairs are adopted, and the locking device is included; and the T-shaped rod is moved to the assigned position according to using requirements and locked through the locking device, the flexibility of the device is guaranteed, and structural stability of the device is guaranteed.