Metal-doped carbon materials, as one of the most important electrocatalytic catalysts for CO2reduction reaction (CO2RR), have attracted increasing attention. Herein, a series of Cu cluster embedded highly porous nanofibers have been prepared through the carbonization of electro-spun MOF/PAN nanofibers. The obtained Cu cluster doped porous nanofibers possessed fibrous morphology, high porosity, conductivity, and uniformly dispersed Cu clusters, which could be applied as promising CO2RR catalysts. Specifically, best of them, MCP-500 exhibited high catalytic performance for CO2RR, in which the Faradaic efficiency of CO (FECO) was as high as 98% at −0.8 V and maintained above 95% after 10 h continuous electrocatalysis. The high performance might be attributed to the synergistic effect of tremendously layered graphene skeleton and uniformly dispersed Cu clusters that could largely promote the electron conductivity, mass transfer and catalytic activity during the electrocatalytic CO2RR process. This attempt will provide a new idea to design highly active CO2RR electrocatalyst.