Only lawyers can read the file?

No, the key is which stage the "file is in the procuratorate" belongs to. If it is the stage of examining and approving the arrest, the defense lawyer cannot consult it. If it is the stage of examination and prosecution, the defense lawyer can consult and copy it.

Legal basis:

Article 40 of the Criminal Procedure Law of People's Republic of China (PRC) * * * Since the people's procuratorate examines and prosecutes the case, the defense lawyer may consult, extract and copy the case file. Other defenders may also consult, extract and copy the above materials with the permission of the people's court or the people's procuratorate.