The research of the thematic unity is specifically important. Since it is a new approach and a new model of the Qur’anic tafsīr. It links with the other words of the Qur’an those are similar to the topic like the linked of the Qur’anic words in the science of coherences, the thematic tafsīr, and the Qur’anic context. The study aims firstly to define the thematic unity, its importance, and its types, then to highlight the relationship of the thematic unity with the other Qur’an sciences, especially with the science of coherences, the thematic tafsīr, and the Qur’anic context. The study relied on the inductive method to analyze the views of the scholars and interpreters in that subject. Furthermore, the analytical method is applied to prove the relationship between the thematic unity and the other sciences of the Qur’an. The most important result is that the research proved that the relationship of the thematic unity with other Qur’an sciences is very close to understand the Qur’an accurately and properly.