The sacrum fused with ilium in a chinese water deer (Hydropotes inermis) was observed. The sacrum consists of four sacral vertebrae which was fused each other. In the ventral part of the fused pelvis, on the left, there was a 20.19 mm gap at the dorsolateral part of the sacroiliac articular part which is in between the promontory and the cranial border of the first ventral sacral foramen. On the right, there was a 14.34 mm gap at the dorsal part of sacroiliac articulation. In the dorsal view of the fused pelvis, the wing of sacrum and the wing of ilium were fused tightly, so that the boundary of the two bones was not recognizable.