The invention relates to a PRP separating device, and relates to the technical field of blood separating devices.The PRP separating device comprises a PRP cabin, a serum cabin and a blood cell cabin which are sequentially arranged, the blood cell cabin comprises a cabin tube, a tail cap and a silica gel cap, the tail cap is in threaded connection to the outer wall of the cabin tube, and the silica gel cap is arranged on the tail cap and abuts against the inner wall of the cabin tube; the end, facing the interior of the cabin pipe, of the silica gel cap is open; the silica gel cap is provided with a connecting pipe extending out of the tail cap, the connecting pipe is detachably connected to the silica gel cap, and the end, located outside the tail cap, of the connecting pipe communicates with a balloon. The blood cells are subjected to closed storage and sterile sampling through the separable balloon, it is guaranteed that the blood cells do not make contact with air in the transferring process, and the detection precision of the blood cells is guaranteed.