The copyright of the best-selling book Chang 'an Twelve Hours belongs to the author or the publishing house. The specific protection period and method may vary according to the country and region. In China, according to the copyright law, the term of copyright protection of an author is unchanged for life from the date of creation, but the copyright of the work can be authorized to a third party for a certain period of time. The specific period is negotiated and agreed upon by both parties. The copyright of " Chang 'an Twelve Hours " may have been authorized to be published and disseminated by multiple publishing houses and platforms. The specific protection period and scope of rights may vary according to the usage method and contract terms. It was important to note that any work enjoyed copyright protection once it was produced. However, copyright is not omnipotent. Some movies and TV series may already be protected by other laws such as trademark law and patent law, so it needs to be analyzed on a case-by-case basis.