To solve the problem of water resources acquisition in arid regions and special environment, inspired by the hierarchical transmission system of plant vein "main vein-branch vein", this study makes use of the natural advantages of the hydrophobic background to reduce the evaporation of droplet retention and the hydrophilic channel to drive the directional convergence of droplet by the capillary effect and Laplace pressure. The Janus membrane (PVDF@TiO2) was successfully fabricated by using the multi-layer electrospinning technique. To impart the special wettability required for fog water collection, the membrane surface was modified through UV mask irradiation. A bionic mixed-wettability surface mimicking leaf veins was constructed on the TiO2-containing side: the hydrophobic regions reduce droplet retention and evaporation loss, while the hydrophilic leaf vein channels efficiently capture and guide fog droplets for directional transport. This dual mechanism synergistically optimizes the entire fog water collection process. The Janus membrane with biomimetic leaf veins achieved a fog water collection rate of 44.335 +/- 0.64 mg cm- 2 min- 1. This study provides a novel approach for developing high-performance fog water collection membrane materials through a synergistic strategy of 'structural design-material composites-surface modification'.