Article 33 of China's Lawyers Law stipulates: "From the day when the criminal suspect is interrogated for the first time by the investigation organ or compulsory measures are taken, the entrusted lawyer has the right to meet the criminal suspect and defendant with the lawyer's practice certificate, law firm certificate, power of attorney or legal aid letter to learn about the relevant situation. Lawyers meet with criminal suspects and defendants without being monitored. " Therefore, it is very important to entrust professional criminal defense lawyers to meet effectively and provide them with procedural legal help and substantive legal advice for safeguarding the legitimate rights and interests of criminal suspects and defendants.