Self-powered sensors with high sensitivity and low-cost fabrication are promising for a wide range of applications, however, the stretchability of the devices has been a long-standing challenge. Here we present a newly-designed hyper-stretchable self-powered sensor that can withstand strain as large as 300% by fabricating piezoelectric poly[vinylidene fluoride] (PVDF) micro/nanofibers into a self-similar structure through helix-electrohydrodynamic direct-writing and self-organized buckling. Helix-electrohydrodynamic direct-writing is able to deposite serpentine micro/nanofibers with diverse geometries in a low-cost, large-scale and additive manner. Self-organized buckling utilizes the driven force from the prestrained elastomer to assemble serpentine fibers into ultra-stretchable self-similar architecture. Quantitative analysis provides detailed insights into the establishment of serpentine design and printing rules for self-similar fibers. The hyper-stretchable self-powered sensors have shown repeatable and consistent electrical outputs with high sensitivity. Meanwhile, such sensors can simultaneously measure different physical quantities, such as stretching, pressure and impulse rate, which is attractive for wearable electronics applications.