Signature-masked authentication is a type of authentication that a user can obtain services when the service provider ensured that the user has the corresponding credentials issued by a trusted central authentication (CA). In this paper, we introduce a new quantum signature-masked authentication scheme based on private key, in which, the centre of CA exports not only the original credential that certificates for the user by adding the user’s secret information but also private key between the user Alice and the service provider Bob. The shared private key makes it possible for the communicators to protect their encoded quantum message from CA cheating. It is proved that the scheme can resist the forgery attack, impersonation attack and outside attack. Also, as a potential application of the scheme, an electronic voting method by using signature-masked authentication is introduced.