In order to study the crack resistance of recycled concrete beams with high replacement rate, this paper changes the replacement rate of recycled aggregate and the mixing rate of basalt fiber, and analyzes its influence on the crack resistance of recycled concrete beams. Through ANSYS finite element simulation, the cracking load, yield load, cracking deflection, yield deflection, cracking stress and yield stress of RAC beams are obtained. It can be seen from the analysis that the replacement rate of recycled aggregate and the content of basalt fiber have a great influence on the crack resistance of the beam. When the replacement rate of recycled concrete is 70% and the content of basalt fiber is 3 kg/mm2, the crack resistance is the most obvious.