The book “Khorasan Conquests” written by Abolhasan Madaeni (135-225 AH)is among the most ancient works about the history of Khorasan. Although like other works of Madaeni and many historians of the early centuries AH we have not received a copy of this book, it seems that this book has not been overlooked by the historians of the next periods and probably some of its parts are quoted and maintained in the works of these writers. Considering this assumption, the author has adopted a library research to investigate the historical resources and many parts of these books have been carefully observed and extracted especially Tabari`s book “Tarikh Al-Omam, va Almoluk”. These extractions were compiled in form of 160 independent reports. Analyzing the content of these reports provides much information about narrators of Madaeni in this book, its beginning and end, its content and features, as well as its advantages.