If you have filed an application for trademark registration in Chinese, the certificate of registration will be in Chinese. Likewise, if your application is made in English, the certificate will be in English.
Additionally, even if you have made an application in English and written to the Intellectual Property Department in Chinese, they will respond to you in Chinese. However, when your application has been accepted by the Department, the certificate of registration, the particulars of your application’s publication and any opposition proceedings will be in English.
Bibliography:Intellectual Property Department, ‘Trade Marks Ordinance (Cap. 559)’: https://www.ipd.gov.hk/eng/faq/trademarks/tm_cap559.htm