The invention provides a carbon fiber composite material, a preparation method thereof and a carbon fiber composite board material. The carbon fiber composite material comprises a carbon fiber composite material body, and further comprises a composite transition layer, wherein the composite transition layer is in contact with the surface of the carbon fiber composite material body; raw materials for forming the composite transition layer include thermosetting resin and a curing agent; the degree of functionality of the thermosetting resin is greater than or equal to 3. Through use of the composite transition layer, the surface structure of the carbon fiber composite material can be changed, the surface polarity of the carbon fiber composite material body can be enhanced, so that adhesion between a carbon fiber-reinforced composite material body and coating is improved and implementation of industrialization during coating of the carbon fiber-reinforced composite material is facilitated.