Abstract: Cryptanalysis of the forward-secure blind signature scheme proposed by He Junjie et al. showed that the scheme does not satisfy forward security. An improved forwardsecure blind signature scheme was proposed. Analysis results showed that the improved scheme has forward security under the assumption which make solving the square root and 2^l-th root of a quadratic residue hard, and its unforgeability dependends on the hardness of discrete logarithm problems and the problems of computing 2^l-th root of a quadratic residue.