The invention provides a lithium ion battery diaphragm and a high temperature thermal-stable lithium ion battery, which relate to lithium ion batteries. The diaphragm comprises a polyolefin microporous membrane which acts as a basic layer, wherein a nano ceramic material coating is manufactured on one side surface or two side surfaces of the polyolefin microporous membrane; and compositions of the nano ceramic material coating comprise any one of a zirconium oxide, an aluminum oxide, a silicon oxide, a titanium oxide, a silicon nitride, a boron nitride and an aluminum nitride or a combination of any oxide and any nitride, and additionally comprise binders. Since a high temperature resistant nano ceramic material is led into the surface of a conventional diaphragm, an insulating property better than the insulating property of the conventional diaphragm is provided, further internal insulating property damage brought by thermal contraction of the conventional diaphragm, which leads to thermal runaway of the lithium battery, is avoided particularly at high temperatures of 130 DEG C, 150 DEG C and 180 DEG C, and thereby the high temperature thermal stability of the lithium ion battery is improved and the safe reliability of the lithium ion battery is increased.