Yes, under PRC law, employers must sign written employment contracts with their PRC employees (except for those part-time employees who are normally paid on an hourly basis; in which case, their employment contracts could be oral).  As a good practice, it is recommended that an employer sign a written contract with its PRC employees before the commencement of employment, though the minimum requirement set by PRC law is to have the written contract signed within one month after the employee starts work.  An employer who fails to meet this deadline will be required, during the first year of employment, to pay double the salary to the employee from the second month of employment until the contract is signed (unless the delay is due to the employee’s delay or refusal to sign the contract).  After one full year of employment, if the employer still fails to sign a written employment contract, it will be deemed to have concluded an open-term employment contract with the employee, which is very difficult to terminate.