One of the key problems in the complex dynamics of cable?stayed bridge is the large vibration of cables resulting from the matching relation between the local and global modal frequencies. In this paper,based on the transfer matrix method,the sensitivity of global modal frequency to CFRP cable was investigated. The deck and tower of cable?stayed bridge are regarded as Euler?Bernoulli beam with discrete elastic supports,respectively. Their corresponding differential equations governing the motion of deck and beam are obtained. Then,the eigen frequencies of global modes are obtained by transfer matrix method. A cable?stayed bridge with single tower in Changsha is taken as an example,and the sensitivity of the stiffness of cable,tower and deck to global modal frequencies was studied. The results shows that the global modal frequency is considerably sensitive to the stiffness of cables and the CFRP cable can be used to replace steel cable in order to reduce and control the vibration of cables.