The invention discloses a method for preparing assembled integrated boards. The method comprises the following steps: first weighing the following raw materials in parts by weight: 15~25 parts of geopolymer cement, 15~35 parts of light ceramsite, 45~53 parts of modified mortar and 2~5 parts of straw fiber, then performing dry mixing on the raw materials in a stirrer for 2~8 minutes to obtain a rawmaterial mixture, weighing a certain amount of tap water, adding an additive to the tap water, then adding the tap water mixed with the additive to the raw material mixture, stirring for 3~8 minutesto obtain a slurry, pouring the slurry into a steel mold coated with an alkali-resistant plastic mesh cloth, placing polyethylene sheet with thickness of 70 mm and steel wire mesh sheets with thickness of 2 mm on both sides when the slurry is evenly spread to a thickness of 25 mm, pouring the slurry, adding a layer of the alkali-resistant plastic mesh cloth to the slurry when the thickness of theslurry reaches 25 mm, shaking and compacting with a vibrator, smoothing, demolding after 60~90 minutes, and natural curing for 7~10 days. The method replaces polystyrene particles with light inorganicceramsite to increase straw fiber and improve the tensile strength and impact resistance of the board, and the board has the characteristics of cracking resistance, environmental friendliness and soon.