Roof rack fixing structure

The present invention discloses a roof rack fixing structure, used to fix a roof rack on a car top. The roof rack fixing structure includes a frame case with an opening; a first fastener; a second fastener; and a knob rod. With the implementation of the present invention, the roof rack fixing structure is firmly combined with the roof rack; more than one combining positions provided by the second fastener to be adaptive to various cars; and the position of the first fastener complies with the width of the roof rack rods on the car with no risk of loosening from it; moreover, with further implementation of an anti-theft lock, the roof rack fixing structure can be locked and secured and the risk of driving due to movement or loosening of the roof rack fixing structure is eliminated.