The invention relates to a 2D carbon/silicon-silicon carbide composite material pin preparation method and a preparation method and structure of a 2D carbon/silicon-silicon carbide composite material pin preform. The pin preparation method comprises 1, preparing a preform through horizontal paving (0 degree)-inclined paving (45 degrees) alternative laying of a 2D carbon fabric, graphite mold-based setting and carbon fiber vertical seaming on the multilayer carbon fabric, 2, depositing a pyrolytic carbon protective layer in the preform, 3, carrying out chemical vapor infiltration (CVI) to obtain a silicon carbide base, 4, cutting a flat blank to obtain a strip-shaped pin blank with the square section, 5, carrying out CVI silicon carbide protection of exposed fibers, 6, carrying out reactive melt infiltration (RMI) treatment, 7, milling the pin blank to obtain a pin with a standard size and 8, carrying out examination to obtain a carbon/silicon-silicon carbide composite material pin finished product. Through combination of CVI and RMI, the preparation method has the advantages of low production cost, short production period, low product porosity, high density and batch production. The ceramic-based composite material prepared by the CVI and RMI has shear strength of 80-100MPa at the room temperature.