With the development of the concept of composite materials, in order to further explore the mechanical properties of composite modified recycled concrete under the coupling effect of NS (nano-SiO₂) modified recycled coarse aggregate and PVA(polyvinyl alcohol) fibers, slump, cubic compression, axial compression, splitting tensile and flexural tests were carried out to study the working performance and mechanical performance changes of modified recycled coarse aggregate concrete with increasing PVA fiber content under different substitution rates. The results show that the slump of concrete increases with the increase of fiber volume. The damage of concrete is brittle, and the damage pattern of recycled concrete mixed with fiber is better. When the fiber volume content is 0.05 vol% and 0.10 vol%, the cubic compressive strength, ultimate bearing capacity, splitting tensile strength, folding strength and static elastic modulus will decrease under different regeneration and replacement rates, but all the strengths will exceed and increase when the fiber volume content is 0.15 vol%. PVA fiber will reduce the ultimate compressive bearing capacity and have different positive and negative effects on the peak strain. It is recommended to add PVA fiber with a volume content of 0.1 vol%. If PVA fiber is needed, it is recommended to use it when the regeneration and replacement rate is less than 30 wt%. In addition, it is found that the modified reclaimed coarse aggregate has good performance and can effectively replace natural aggregate or be mixed with natural aggregate in practical engineering.