The invention discloses a carbon fiber board and a preparation technique for a carbon fiber board. The carbon fiber board comprises a carbon fiber cloth layer and a carbon fiber yarn layer, the carbon fiber cloth layer is composed of longitudinal carbon fiber and transverse carbon fiber in a vertical alternating interweaving mode, the carbon fiber yarn layer is composed of carbon fiber in a vertical bidirectional interweaving mode, both the carbon fiber cloth layer and carbon fiber yarn layer are provided with grouting agent through dipping, and the carbon fiber yarn layer is arranged between adjacent carbon fiber cloth layers. The technique for preparing the carbon fiber board includes that interweaving the carbon fiber cloth; interweaving the carbon fiber yarn in a bidirectional mode; dipping the carbon fiber cloth layer and carbon fiber yarn layer in epoxy resin glue; locating the carbon fiber yarn layer between the adjacent carbon fiber cloth layers; pre-heating the obtained board in a pre-heating box, putting in a mold, pressurizing under a constant temperature, and demolding after cooling. The carbon fiber board overcomes the problem that the current products on the market only highlight the tensile strength; the carbon fiber board has high tensile strength and enables the compression resistance, bending resistance, torsion resistance and shearing resistance to be greatly improved, and the carbon fiber board is composite carbon fiber board with good overall performance.