How to register a marriage
How to get married (UK national to Chinese national)
• If resident here and you intend to marry a Chinese national, you will need a Certificate of No Impediment (CNI). You must be resident in China for a minimum of 21 continuous days before making a notice of intention to marry. (The 21 days is counted from your last entry stamp into China, previous stays of 21 days in China are invalid).According to the Marriage Law of the People’s Republic of China, no marriage may be contracted before the man has reached 22 years of age and the woman 20 years of age. (Source link:
http://www.novexcn.com/marriage_law.html ).
• To obtain a CNI, you will need to go to either the Embassy or nearest Consulate, with your passport and your partner’s passport or ID card, complete a notice of intention form and sign an affidavit to state that you are free to marry. If previously married, then we need to see either a divorce or death certificate.
• The notice will be displayed for a further 21 continuous clear days, starting the following day of application. If no objection is given, a CNI will be issued in both Chinese and English languages. By Chinese law you must marry in the place of your fiancé (e)'s hukou. If their hukou registration is outside the Consular Jurisdiction that you reside in, you will need to contact the local Marriage Bureau in their Province, to find out if they accept the Embassy or Consulate’s paperwork where you made the application.
http://ukinchina.fco.gov.uk/en/help-for-british-nationals/living-in-china/how-register-marriageWilly... hope it could help.