Proxy signatures are very useful tools with which a potential signer can delegate his signing power to a proxy signer who signs a message on behalf of the original signer. A blind signature is the concept with a salient feature that the signer cannot make a linkage between the blind signature and the identity of the requester. Therefore, it is very suitable for electronic commerce. On the basis of the blind Schnorr signature, this paper presents a digital proxy blind signature scheme, which satisfies the security properties of both the blind signature scheme and the proxy signature scheme.