A syringe including a tube, a first plunger, a second plunger and a plunger rod assembly is disclosed. The tube has one end serving as an injection end and the other end coupled with a cap. The first plunger is disposed in the tube. A filled portion extends through the first plunger. A first chamber is formed between the first plunger and the injection end. The second plunger is disposed in the tube and has a fixing hole. A second chamber is formed between the first and second plungers. The plunger rod assembly comprises a rod and a blocker. The rod has a neck portion and at least one engaging portion. The blocker is arranged on one side of the neck portion and is capable of being inserted into the filled portion. The blocker is capable of being removed from the first plunger and being received in the fixing hole.
