The invention relates to a concrete-steel truss composite beam torsion test device and a composite beam fixing frame. The composite beam fixing frame includes a steel truss fixing bracket and a concrete slab fixing bracket. The steel truss fixing bracket includes a left fixing plate and a right fixing plate which are spliced together in the left-right direction and which are fixedly connected byfirst bolt locking members. The concrete slab fixing bracket includes a first fixing bracket and a second fixing bracket which are spliced together in the up-down direction. The bottom of the first fixing bracket is provided with an upper string receding groove. The first fixing bracket and the second fixing bracket are fixedly connected through second bolt locking members. The first fixing bracket and the second fixing bracket are provided with first and second clamping surfaces for clamping and fixing the two side surfaces of a concrete slab respectively. The concrete-steel truss composite beam torsion test device can perform a torsion test on a concrete-steel truss composite beam with a triangular steel truss cross section.