People's Republic of China (PRC) citizens' personal freedom is inviolable.

No citizen shall be arrested unless approved or decided by the people's procuratorate or decided by the people's court, and shall be executed by the public security organ.

It is forbidden to illegally detain or deprive or restrict citizens' personal freedom by other means, and it is forbidden to illegally search citizens' bodies.

Article 238 of the Criminal Law

Crime of illegal detention Whoever illegally detains others or illegally deprives others of their personal freedom by other means shall be sentenced to fixed-term imprisonment of not more than three years, criminal detention, public surveillance or deprivation of political rights. Those who are beaten or insulted shall be given a heavier punishment.

Whoever commits the crime mentioned in the preceding paragraph and causes serious injuries shall be sentenced to fixed-term imprisonment of not less than three years but not more than ten years; Whoever causes death shall be sentenced to fixed-term imprisonment of not less than ten years. Whoever uses violence to cause disability or death shall be convicted and punished in accordance with the provisions of Articles 234 and 232 of this Law.

Whoever illegally detains another person or detains another person in order to claim debts shall be punished in accordance with the provisions of the preceding two paragraphs. Any functionary of a state organ who commits the crimes mentioned in the preceding three paragraphs by taking advantage of his power shall be given a heavier punishment in accordance with the provisions of the preceding three paragraphs.

See for yourself whether it is legal or not.