Can Guokang use Chinese mobile phone cards?

Yes.

According to the Xiaohongshu travel guide, Chinese mobile phone cards can be used in the Kokang area, but some conditions need to be met. The Kokang area needs to be within the network coverage of China Telecom, which means it needs to be a user of China Telecom. Secondly, international roaming service needs to be activated so that the Chinese mobile phone card can be used in the Kokang area.