Regarding Arabic loanwords in Farsi, the dominant view is that the arrival of Arabic words in the Islamic period, that is, after Islam came to Iran, was mostly in Persian in the sixth and seventh centuries and their presence in Persian texts is strong and intensified. In this research, we are trying to show, as far as the documents are available, that the introduction of Arabic words into Persian language happened a long time ago,And this cultural-linguistic exchange has probably taken place since the time when Iranians and Arabs have been in contact with each other, that is, since the Achaemenid period.