Composing and writing are both terms related to creating music, but there are some differences in specific meanings.

Composition generally refers to the process in which a composer writes musical ideas on the score using graphic symbols. Composers express their musical ideas by converting musical ideas into notes, time symbols, chord marks, etc. in the score. The process of composing involves the creation of music's melody, harmony, rhythm, etc., and how to integrate them together to form a complete work. Therefore, composition focuses more on the process of music creation.

Writing can also refer to the process by which a composer transforms musical ideas into scores, but more commonly refers to the process of arranging, revising, editing and arranging already composed music. The writing process may include revising the score, adding and deleting elements of the music, determining the orchestration of instruments, adjusting the structure of the music, etc., in order to achieve the best musical effect. Writing can be seen as the further development and improvement of composition to achieve better musical expression.

In summary, composing puts more emphasis on the creativity and originality of music, while writing focuses more on the arrangement and modification of existing musical works.