If the theft is minor, it can be criticized and educated, and punished according to the rules and regulations of the employer.
If the circumstances are serious, you should call the police and hand it over to the police.
According to Article 264 of the Criminal Law of People's Republic of China (PRC), whoever steals public or private property in a relatively large amount, or commits theft for many times, burglary with a weapon or pickpocketing shall be sentenced to fixed-term imprisonment of not more than three years, criminal detention or public surveillance, and shall also or only be fined.
If the amount is huge or there are other serious circumstances, he shall be sentenced to fixed-term imprisonment of not less than three years but not more than ten years and shall also be fined.
If the amount is especially huge or there are other especially serious circumstances, he shall be sentenced to fixed-term imprisonment of not less than 10 years or life imprisonment, and shall also be fined or confiscated.