If, according to the above regulation, you have to apply at the Belgian Embassy or Consulate in China, all depends on the place you are registered and / or living. You have to apply at the Belgian diplomatic mission who has your permanent or temporary residence in its jurisdiction.
If you are permanent resident at the same address that is mentioned on your Hukou (Chinese family booklet), it??s easy to know which mission has your city / province in its jurisdiction.
If you are temporary resident in a different place, you should provide a temporary residence card from the province where you are living and apply at the mission who has this province in its jurisdiction.