An artificial timer and preparing method thereof. The artificial timber includes the following components in parts by weight : 35-50 parts of cellulose, 20-35 parts of hemicellulose and 15-35 parts of lignin, wherein the artificial timber has a density of 0.01-0.05 g/cm3. The preparing method includes : (1) dissolving 15-35 parts by weight of lignin, 35-50 parts by weight of cellulose and 20-35 parts by weight of hemicellulose with an ionic liquid; (2) cleaning and replacing it with water to obtain a lignocellulose hydrogel; and (3) drying the lignocellulose hydrogel to obtain an artificial timber. The prepared artificial timber is large in specific area, low in density, low in material energy consumption, moderate in condition and easy for operation. The obtained artificial timber is regular in shape and shaped like a sandy beige cylinder without obvious damage and deformation, which indicates that such artificial timber with high specific area has well molding capacity.