In this study, aligned nanofibers have been fabricated by magnetic electrospinning, through the incorporation of magnetic nanoparticles (MNPs) into poly(lactic-co-glycolide) (PLGA) nanofibers. We further optimized the magnetic electrospinning process by systematically investigating the influence of the MNP and its content on the alignment of nanofibers. The biological effect of the aligned magnetic-electrospun nanofibers has been investigated by culturing C2C12 myoblasts on different nanofibers. The results indicated that the cells migrated and extended along the fiber arrangement. Because of the synergic effect of the magnetic nanoparticles on the nanofibers, the cell's adhesion and proliferation is much more enhanced in our aligned nanofibers than the traditional ones in this experiment. Therefore, the magnetic-electrospun nanofibers could be a good candidate for an aligned tissue engineering scaffold.