The porphyrin-based MOFs formed by combining Zr₆ clusters and porphyrin carboxylic acids with clear M-N₄ active centers show unique advantages in electrocatalytic reduction of CO₂ (CO₂RR). However, its conductivity is still the bottleneck that limits its catalytic activity due to the electrical insulation of the Zr cluster. Therefore, the porphyrin-based MOFs of PCN-222(M) (M = Mn, Co, Ni, Zn) with explicit M-N₄ coordination were combined with the highly conductive material carbon nanotube (CNT) for discussing the influence of metal centers on the CO₂RR performance based on theoretical calculations and experimental observations. The results show that the PCN-222(Mn)/CNT, PCN-222(Co)/CNT, and PCN-222(Zn)/CNT all exhibit high selectivity to CO (FE_CO > 80%) in the range of -0.60 to -0.70 V vs. RHE. The FE_COmax of PCN-222(Mn)/CNT (-0.60 V vs. RHE), PCN-222(Co)/CNT (-0.65 V vs. RHE), and PCN-222(Zn)/CNT (-0.70 V vs. RHE) are 88.5%, 89.3% and 92.5%, respectively. The high catalytic activity of PCN-222(Mn)/CNT and PCN-222(Co)/CNT comes from the excellent electron mobility of their porphyrin rings and their low ΔG_*COOH (0.87 and 0.58 eV). It reveals that the strength of backbonding π of the transition metal and its influence on the electron mobility in the porphyrin ring can affect its CO₂RR activity.