The invention discloses an SM2 signature algorithm security verification method based on an random number unknown. The method comprises the following steps: (1) signing N+1 messages M respectively by adopting an SM2 signature algorithm, and injecting an error into every SM2 signing in order that identical errors occur in signing results s of identical set bit parts of a random number k used in every signing; (2) subtracting error signing results s in other N signing respectively from the error signing result of first signing with reference to an equation of the error signing result s of first signing to obtain an equation set, namely, a lattice attack model; and (3) solving the lattice attack model, recovering all bits of the random number k used in every signing, substituting the recovered bits into an equation for calculating corresponding signing results s to obtain a private key dA, and judging that the SM2 signature algorithm is unsafe if the private key dA is a correct private key. Through adoption of the method, the security capability of the SM2 signature algorithm in attack resistance can be analyzed more effectively and comprehensively.