Chinese authorities do not check whether a trademark registration applicant actually provides the goods or services of the class he/she is applying for. As long as there are no previous similar applications, the authorities can approve the accept the application.
Therefore, an entity can register your trademark to provide goods and services similar to yours, and pretend to be you.
Another risk is that an entity registers your trademark with the sole purpose of selling it back to you. In such case either you give-in, or you might need to re-brand, because in China it is very hard to apply for the ‘well-known’ trademark status in trademark infringement cases.