Text messages are documentary evidence of the answer.

Mobile phone short message belongs to documentary evidence: the similarity between mobile phone short message and documentary evidence lies in the same function, and both use recorded content or expressed meaning to prove facts. The difference is that the recording method is different from the recording medium. Ordinary documentary evidence records certain contents on paper in the form of words and symbols. Mobile phone short messages use digital signals to record the same content on non-paper storage media.

The view that short messages belong to audio-visual materials: objectively, short messages are most similar to audio-visual materials. First, perception. Mobile phone short messages and most audio-visual materials need to be transformed into words or graphics by means of certain tools or means and then perceived by people; Second, the form of existence. Stored on non-paper media in the form of magnetic media instead of text symbols; Third, there is no difference between the original and the copy.

The author believes that the evidence form of mobile phone short messages in civil litigation should belong to documentary evidence. First of all, as one of the types of data messages, mobile phone short messages also record and reflect the sender's ideological content through words, symbols, graphics and other forms, and the ideological content can be recognized and copied by people. Secondly, documentary evidence exists on the basis of some substance. We should make an extended explanation of material carrier, which is not limited to paper, but can include furniture, plastics, photos and so on. It should also include new magnetic media carriers, such as mobile phones and computers, which are constantly emerging with the development of science and technology. As long as it can store and preserve certain signals, it can be used as evidence. Third, documentary evidence consists of material carrier and the content of proving the case, which are indispensable.