Generally speaking, the subtitle of a master's thesis can be modified. However, when modifying subtitles, you need to pay attention to the following points:

Necessity of modification: Before modifying subtitles, it is necessary to confirm the necessity of modification. If there is no problem with the subtitle or it has little influence on the paper, it is not recommended to modify it.

Conform to academic norms: Subtitles should conform to academic norms and requirements, and accurately reflect the content and theme of the paper. When modifying the subtitle, we should ensure that the new subtitle is concise and consistent with the overall style and language level of the paper.

Consistency: the subtitle should be consistent with the main content of the paper. When modifying the subtitle, we need to pay attention to the echo relationship between the subtitle and the theme of the paper, and the first-level title and the third-level title to avoid contradiction or repetition.

Does not affect the structure of the paper: subtitle is an important part of the structure of the paper and should be consistent with the overall structure of the paper. When modifying the subtitle, it is necessary to pay attention to adjusting the relevant content to ensure that the overall structure of the paper will not be destroyed.