A voucher verification auxiliary method is provided, including: when a user device is approaching a voucher verification auxiliary device, generating an encryption key for the user device to encrypt voucher data with the encryption key to generate first encrypted data; reading and decrypting the first encrypted data to obtain the voucher data; encrypting the voucher data to generate and transmit second encrypted data to a verification center; decrypting the second encrypted data to obtain the voucher data, generating a verification result after verifying the voucher data, encrypting the verification result to become third encrypted data, and transmitting the third encrypted data back to the voucher verification auxiliary device; decrypting the third encrypted data to obtain the verification result; transmitting the verification result to a voucher receiving terminal. A voucher verification auxiliary device and a voucher verification auxiliary system are also provided.