Membranes with the functions of waterproofness and breathability are of great interest due to their huge scientificand commercial value in many practical applications. However, designing such membranes with a desirable performance bysimple and efficient fabrication process remains a tremendous challenge. Herein, novel binary structured composite fibrousmembranes were developed for waterproof and breathable applications via simple one-step multi-jet electrospinningtechnology. This composite membranes were made up of polyvinylidene fluoride (PVDF) and polyacrylonitrile (PAN). PVDF was incorporated into the PAN fiber matrix as a modifier to improve the hydrophobic behavior of fibers. Meanwhile,PVDF microspheres/fibers were employed as building blocks to orderly embed in PAN/PVDF fiber framework, impartingthe composite membranes with fluffy micro-nano hierarchical structures. Consequently, with the integrated features of robusthydrophobicity as well as elaborate fiber-microsphere binary structure, the resultant composite membranes exhibitedsynergistically modest waterproof and breathable performances with the hydrostatic pressure of 18.04 kPa, water vaportransmittance (WVT) rate of 4.65 kg m-2 d-1, and air permeability of 64.19 mm s-1. This simple preparation process andunique composite structure may provide a new insight to design and fabricate waterproof and breathable membranes forvariously potential applications, including the protective clothing, separation membrane, and filter.