1. The supplementary card of the China Unicom mobile phone number card can be canceled. If there is no special agreement on your China Unicom supplementary card, you can bring your valid ID to the China Unicom business hall to handle account cancellation.

2. Due to differences in product policies among provinces and the inability to query the specific information of your number, if you do not understand the account cancellation rules of the supplementary card, you can also call China Unicom customer service where the number belongs for consultation.