Legal analysis: Mobile phone signature refers to electronic signature. Whether an electronic signature has legal effect depends not on whether it is made by mobile phone or computer, but on whether it conforms to the reliable electronic signature stipulated by law. An electronic contract signed with a reliable electronic signature has legal effect.

Legal basis: Article 13 of People's Republic of China (PRC) Electronic Signature Law shall be deemed as reliable if the electronic signature meets the following conditions at the same time:

1. When electronic signature production data is used for electronic signature, it belongs exclusively to the electronic signer;

2. When signing, the electronic signature production data is only controlled by the electronic signer;

3. Any changes to the electronic signature after signing can be found;

Any changes in the content and form of the data message after signing can be found. The parties can also choose to use electronic signatures that meet their agreed reliable conditions.