The invention provides a mold-releasing type complexing agent with effects of resisting a high temperature of more than 1450 DEG C, insulating heat and demolding and a preparation method thereof. The mold-releasing type complexing agent comprises the following raw materials in percentage by weight: 20-60% of nano colloidal silicon dioxide solution; 5-30% of composite oxide ultramicro (0.1-1.0 microns) powder including Na, Mg, Ca, Fe, Li, Al, Si, B, Zr and other elements; 0.2-2% of water-based dispersing agent;0.02-0.5% of water-based thickening agent and the balance of water; and the sum of the weight of the components is 100%. According to the mold-releasing type complexing agent with effects of resisting high temperature, insulating heat and demolding, the nano colloidal silicon dioxide solution is cooperated with the ultramicro (0.1-1.0 microns) multielement composite oxide powder, so that the excellent performances of high temperature resistance, heat insulation, demolding, environment protection and the like are achieved, the thermal fatigue resistance of the mold surface is effectively improved, and the service life of the mold is prolonged. The mold-releasing type complexing agent with effects of resisting high temperature, insulating heat and demolding is particularly applicable to using at the part of a mold directly contacting molten steel in fired mold casting and other high temperature forming technologies of metal.