Nanofibers fabricated through electrospinning technology have been successfully applied in various industries. The filtration advantages of nanosized electrospun fibers, particularly their high filtration efficiency and low pressure drop, make them highly suitable for addressing the problems of particulate pollution. Previous research has shown that the higher surface-to-volume ratios of nanoscale porous fibers contribute to their physical properties. However, little research on the filtration characteristics of charged porous fibers has been reported. Accordingly, this study used electrospinning to fabricate micro- and nanoscale PMMA fibers in order to investigate the surface voltage, pressure drop, and filtration efficiency of charged porous fiber filters. The outcomes showed that porous PMMA fibers were successfully fabricated as the mass ratios of DMF:CHCl3 gradually reached 1:15. After corona discharge, the surface voltage of the fine porous fiber (~500 nm) was –0.650 kV higher than the –0.562 kV voltage of fine smooth fiber. Filtration efficiency was evaluated using particles with an average concentration of 1.16 × 106 and with sizes ranging from 21.58–660.62 nm. After negative corona discharge, the most penetrating particulate size of filters made from fine porous fiber decreased from 168.5 to 121.9 nm, and the penetration rate dropped from 34.09% to 5.84%. For smooth fiber, the most penetrating particulate size remained unchanged at 135.8 nm, but the penetration rate dropped from 32.64% to 18.19%. This study also showed that porous fiber performed better than smooth fiber in terms of surface voltage decay and single fiber efficiency.