Car roof luggage rack assembly

A car roof luggage rack assembly comprises a pair of rails, wherein retaining channels are limited inside the rails. Locking grooves are formed in the inner surfaces of the rails and are communicated with the retaining channels. The car roof luggage rack assembly further comprises transverse beams which are provided with rotary lock cams, and the lock cams are provided with retaining wings. The lock cams are designed to be meshed with the lock grooves in a friction mode during rotation processes, the retaining wings are used to be extended inside the retaining channels, and therefore, the transverse beams are fixed to the rails. By means of the car roof luggage rack assembly, the rails of a car roof luggage rack can be easily adjusted, and the rails can be easily fixed.