Legal analysis: Forging others' signatures constitutes fraud. If it is used for perjury, it constitutes perjury. If it is used to forge government documents, the circumstances are even more serious. Signature has legal effect, and forged signature bears legal responsibility. However, just forging a signature does not constitute a criminal offence, and it is necessary to comprehensively judge whether it constitutes a crime and what kind of crime it constitutes by combining the specific behavior, social harm and harmful consequences after forgery.

Legal basis: Article 171 of the Civil Law of People's Republic of China (PRC), if the actor has no power of attorney, exceeds his power of attorney or continues to act as an agent after the termination of his power of attorney, it will have no effect on the principal without ratification by the principal.