The invention, relating to the technical field of exterior wall organic heat insulation wall and production thereof, particularly discloses a building exterior wall integral solidified organic heat insulation board and a preparation method thereof. The heat insulation board is prepared by using perlite, ordinary portland cement, slaked lime, heavy calcium, sulpho aluminate, zeolite powder, acrylic acid, and water, and carrying out burdening, dry mix, wet mix, diecast, microwave coagulation, depanning and maintenance. Compared with the prior art, the method has the advantages of simple structure, easy obtainment of raw materials, easy preparation; and the heat insulation board has the advantages of small heat conductivity, low water absorption, stable effect of heat insulation, good flame resistance, short production period, and high efficiency. The invention is suitable for large-scale industrial production.