Nanofibers fabricated through electrospinning technology have been successfully applied in various industries. The filtration advantages of nanosized electrospun fibers, particularly high filtration efficiency and low pressure drop, make them highly suited to address problems of particulate pollution. Previous research has shown that the higher surface-to-volume ratios of porous nanoscale fibers contribute to their physical properties. However, little research on the filtration characteristics of charged porous fiber 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 PMMA porous fibers were successfully fabricated as the mass ratios of DMF:CHCl3 gradually reached 1:15. After corona discharging, the surface voltage of the porous fine fiber (~500 nm) was –0.650 kV higher than the –0.562 kV of smooth fine fiber. Filtration efficiency was evaluated using particles in 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 porous fine fiber narrowed 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.