Due to the lack of a regular and stable system and difficulties in budget management, tax affairs during the Mamalik era (648-923) was transforming continuously. Since, part of the Mamalik’ s incomes, like previous governments, was based on collecting taxes from non-Muslim Copts, sources of this period indicate that due to various factors, Mamliks have been forced to make changes in the way of tax reception and its types from non-Muslims. The present paper attempts to answer the question of how Copt’ s taxation has changed over the Mamalik’ s era and how these changes influenced mamalik’ s financial system and incomes? According to the findings of this research, the Copts had a huge impact on the increase of Mamalik’ s incomes by paying taxes of Jizya, Sahlalghale, Mazalim, Mokus, Mavaris, fines, and army equipment tax. Finally, they also have been effective in removing Mamalik’ s financial and economic problems and improving their economic condition