The mechanical properties, survivability of space environment, and thermal properties of CCF700-12K carbon fibers and their composites, are studied based on the localization research of high-strength carbon fiber materials for a major product. The tensile strength of domestic CCF700-12K carbon fibers is 4 706 MPa, with a tensile modulus of 268 GPa. The tensile strength of one-way slabs containing CCF700-12K/F46 composite is 1958.8 MPa, and with a tensile modulus of 144.79 GPa. The results confirm that CCF700-12K carbon fibers show excellent mechanical properties, stable process performance, which can meet the requirements for structrural engineering applications of composite materials.