Detention centers generally do not last more than two months. The time for applying for approval after detention in a detention center shall not exceed seven days. The period of investigation and detention after the arrest of a criminal suspect shall not exceed two months. If the case is complicated or cannot be concluded immediately at the expiration of the time limit, it may be extended for one month with the approval of the people's procuratorate at the next higher level. If the public security organ concludes the investigation and finds that the criminal evidence is really sufficient, it shall be transferred to the procuratorate for examination and prosecution, and if it finds that the criminal evidence is really insufficient, it shall be released.
Legal basis: Criminal Procedure Law of People's Republic of China (PRC).
Article 154 The period of investigation and detention of a criminal suspect after his arrest shall not exceed two months. If the case is complicated and cannot be concluded at the expiration of the time limit, it may be extended for one month with the approval of the people's procuratorate at the next higher level.
Article 89 If a public security organ deems it necessary to arrest a detained person, it shall, within three days after detention, submit it to the People's Procuratorate for examination and approval. Under special circumstances, the approval time can be extended by one to four days.