Abstract: The diamond films is becoming focus in recent years because of their outstanding physical and chemical properties,whereas,the large-area freestanding diamond films have a wilder application in all fields,owing to their structural integrity.In this paper,the research progress and factors which determines the growth uniformity and growth rates of the large-area freestanding diamond films are outlined.Experiments showed that,the higher the microwave frequency is,the faster deposition rate will be; the influence of gas flow rate on the deposition rate has a tendency of decrease after increasing;the design of substrate holders is important to the uniformity of diamond films,the influence of auxiliary gas on diamond films depends on gas species; the addition of traces N₂,O₂can increase the deposition rate.Besides,the applications of the large-area freestanding diamond films in IR windows are prospected.