The development of photocatalytic Suzuki-Miyaura coupling reaction for CC bond formation in organic synthesis will be beneficial to solve environmental problems and reduce production costs. Herein, the porous poly(lactic acid) fiber of graphitic carbon nitride (g-C3N4) coupled with palladium (T-Pd@CN/PLA) was prepared by centrifugal-electrostatic spinning and the alkali treatment, where palladium supported on g-C3N4 (Pd@CN) was synthesized by microwave-assisted deposition. T-Pd@CN/PLA porous fibers showed enhanced catalytic activity and broad substrate applicability for Suzuki-Miyaura coupling reaction with aryl bromides and phenylboronic acid as the substrates at room temperature in air under LED light. The electrons generated by g-C3N4 could be efficiently and rapidly transferred to Pd, and more active sites could be exposed due to the porous structure of the fiber. This work may serve as a guideline on the design of catalytic fibers for the Suzuki-Miyaura coupling reaction, highlighting the effect of light and pore structure on the efficiency.