Rechargeable sodium–oxygen (Na–O2) batteries are of interest due to their high specific capacity, high equilibrium potential output, and the abundance of sodium resources; however, their cycle life is still very poor due to instability of electrolytes and especially the uncontrollable growth of Na dendrites. Herein, as a proof‐of‐concept experiment, a facile and low‐cost strategy is first proposed and demonstrated to effectively suppress growth of Na dendrites by using a fibrillar polyvinylidene fluoride film (f‐PVDF) with nonthrough pore as a multifunctional blocking interlayer. Unexpectedly, the f‐PVDF interlayer endows Na–O2 battery with superior electrochemical performances, including high rate capability and long cycle life (up to 87 cycles), which is superior to those of the compact PVDF (c‐PVDF), PVDF with through pores (p‐PVDF), polyethylene oxide (PEO), and conventional polytetrafluoroethylene (PTFE) counterparts due to the following combined advantages: (1) the stronger CF polar function groups provide a better affinity to Na ions, thus enabling a more homogeneous Na deposition than that of CO function groups in PEO interlayer; (2) compared with c‐PVDF and p‐PVDF interlayers, f‐PVDF holds more electrolyte uptake for higher ion conductivity; (3) the good wettability of the f‐PVDF interlayer with electrolyte benefits Na dendrite suppression compared with PTFE interlayer. Stable and fibrillar polyvinylidene fluoride films (f‐PVDFs) with strongly polar functional groups are prepared as the blocking interlayer for Na dendrites suppression. Surprisingly, the films efficiently suppress dendrite formation and greatly improve the cycle life of Na–O2 batteries, which is attributed to f‐PVDF's high electrolyte uptake, good adhesion to Na ionic flux, and excellent affinity to the electrolyte.