A working method of an NFC dynamic token, comprising the following steps: after detecting that a preset press key is triggered, the NFC dynamic token activates NFC communication and builds connection with a mobile device via NFC channel; when the NFC dynamic token receives a second instruction from the mobile device, the NFC dynamic token obtains a seed key from the second instruction, stores the seed key and sends a message that writing is successful to the mobile device; when the NFC dynamic token receives a third instruction from the mobile device, the NFC uses self-stored seed data to generate a dynamic password and sends the dynamic password to the mobile device via the NFC channel. According to the present invention, the seed key is written into the NFC dynamic token via the NFC channel, which improves security and flexibility of the dynamic token.