cement board and an apparatus used in the method are provided in the present invention the method of manufacturing wood cement board comprising strewing a raw materials mixture of wood cement board on a mold panel to form a mat piling up a plural number of the mats with the mold panels pre pressing the piled mats to reduce the thickness of each mat piling up a plural number of the pre pressed mat main pressing the pre pressed and piled mats and curing the piled mats being main pressed and the apparatus used in the method consists of a piling up machine piling up a plural number of mats formed on a mold panel a pre press machine pre pressing the piled mats to reduce the thickness of each mat a main piling up machine piling up a plural number of the pre pressed mats a main pressing machine main pressing the pre pressed and piled mats and a curing chamber curing the piled mats being main pressed in the present invention since a plural number of mats are piled up before pre press process the pressure effecting on the piled mats can be released slowly to prevent the generation of big negative pressure between mats without delaying pre press process application_number US 56510995 A description fig1 to fig9 relate to an embodiment of the present invention referring now to fig1 a mold panel 102 having an embossed mold surface is put on a conveyer panel 101 and a raw materials mixture is strewed on said mold panel 102 to form a mat 103 said raw.