1, with different objects: the former is set up for criminal suspects and defendants in public prosecution cases and defendants in private prosecution cases, while the latter is set up for private prosecutors, victims and parties involved in incidental civil litigation.
2. Defenders and agents ad litem enter criminal proceedings in different ways. In addition to entrustment, the former can enter the proceedings through the designation of the court, and the agent can enter the proceedings under the entrustment of the principal.
3. The status of defense lawyer is completely different from that of attorney. The former has an independent status and is not influenced by the will of criminal suspects, nor is it interfered by individual groups such as courts and procuratorates. The latter must operate within the scope authorized by the principal according to law, because the agent's behavior not only has the same effect as the principal's behavior, but also bears all the legal effects produced by the principal.