The invention discloses a method for preparing carbon/carbon composite profiles, comprising the following steps: after carbon fiber cloths are impregnated into resins, curing the carbon fiber cloths by way of external tooling pressing or mould pressing after cutting, layering or winding, and preparing carbon/resin based composite profile products after curing and demoulding; carrying out carbonization treatment under the protection of N2 to prepare carbon/carbon composite profile semi-finished products; carrying out supplementary densification treatment on the carbonized carbon/carbon composite profile semi-finished products by metallic or graphite moulds and tooling; carrying out mechanical processing on the carbon/carbon composite profile semi-finished products subjected to supplementary densification to prepare the carbon/carbon composite profile products. The technology of the invention is simple, low in cost and strong in implementation. As carbon additive cloth cutting, layeringor winding and external tooling pressing or mould pressing curing and shaping modes are adopted, the prepared carbon/carbon composite profiles have a series of advantages as follows: the shaping modeis simple; the sizes of the products are hardly limited and mechanical processing is unnecessary in the thickness direction, thereby having superior performance-price ratio.