In order to obtain the tightening characteristics of C/C composite material bolt, the tightening torque characteristics of C/C composite material bolt with different structures were studied in this paper. The research can include the variation trend of the torque coefficient K of the bolts in different combinations of gasket material, single nuts and double nuts, scribbling with adhesives and non-scribbling with adhesives. The ultimate torsional resistance of C/C composite material bolt was studied. The results show that the torque coefficient K of the bolts is different from that of the metal bolts. The scribbling with adhesives can obviously improve the clamping force.