The Copyists of the Manuscripts have always made Intentionally and unintentionally mistakes in Manuscripts, and with a this they have distorted the manuscripts.Some of these changes occurred intentionally and were because of the ideological, political, and religious and etc. Others were unintentional, due to inattention, fatigue, and similar reasons.

In Manuscript writing, insufficient linguistic knowledge and Misunderstanding the meaning of some words has caused the mistakes and that has been One of the most important reasons in mistakes and distortion of the Manuscripts.

The present research with a descriptive-analytical method, has attempted while discussing and explaining this factor of Manuscript changes, examined and analyzed examples of these changes and distortions in the Khaqani's Divan who is one of the most difficult Iranian poets to understand.

The result of the present study is that the linguistic factor and Copyists limited knowledge of the language were one of the important reasons for changing the recordings of different versions of Khaqani's Divan.

Copyists due to misunderstanding and limited knowledge about some words of poet and the meaning of this words, changed them and made mistakes in their Manuscripts.