It is illegal to impersonate someone else's signature. If someone else pretends to be my signature without my knowledge, I won't ratify it, I won't bear legal responsibility, and the signatory will bear the responsibility. If it is approved, I should bear the responsibility. Signing on behalf of others is an agency act. If I don't know, I have no right to represent and I don't bear legal responsibility. However, if I know that someone else signed my name without denying it, or that I ratified it, the signature is binding on me and I should bear legal responsibility.

First, the constitutive elements of the crime of impersonation:

1, object element. The object of this crime is the normal social management order, and the object is the right of others to receive education, work and treatment.

2. objective factors. Objectively speaking, the actor enjoys the education that others deserve and the student status, position, identity and treatment obtained by using other people's names, admission notices, forged files and household registration. Representing others or stealing their interests;

3. Main elements. The subject of this crime is the general subject. Mainly master teaching, student status management, account management related personnel;

4. Subjective factors. The subjective aspect of this crime is intentional.

Second, the sentencing standards for the crime of impersonation:

1. Whoever misappropriates or fraudulently uses another person's identity to obtain higher education admission qualification, civil servant employment qualification and employment placement treatment instead of others shall be sentenced to fixed-term imprisonment of not more than three years, criminal detention or public surveillance, and shall also be fined;

2. Whoever organizes or instigates others to commit the acts mentioned in the preceding paragraph shall be given a heavier punishment in accordance with the provisions of the preceding paragraph;

3. State functionaries who commit the acts mentioned in the preceding two paragraphs, which constitute other crimes, shall be punished in accordance with the provisions of combined punishment for several crimes.

Legal basis: People's Republic of China (PRC) Criminal Law.

Article 280-1 The crime of using false identity documents or stealing identity documents refers to the use of forged, altered or stolen resident identity cards, passports, social security cards, driver's licenses and other documents that can prove identity according to law in activities that should provide identity certificates according to state regulations. If the circumstances are serious, they shall be sentenced to criminal detention or public surveillance and shall also or only be fined. Whoever commits the acts mentioned in the preceding paragraph and constitutes other crimes shall be convicted and punished in accordance with the provisions of heavier punishment.

Article 280 bis Whoever steals or fraudulently uses another person's identity to obtain the qualifications for admission to institutions of higher learning, employment of civil servants and employment placement on behalf of another person shall be sentenced to fixed-term imprisonment of not more than three years, criminal detention or public surveillance, and shall also be fined. Whoever organizes or instigates others to commit the acts mentioned in the preceding paragraph shall be given a heavier punishment in accordance with the provisions of the preceding paragraph. State functionaries who commit the acts mentioned in the preceding two paragraphs, which constitute other crimes, shall be punished in accordance with the provisions of combined punishment for several crimes.