Amorphous electrode has been witnessed for enhanced electrochemical performance as unique isotropic nature. Moreover, the fancy structures are beneficial to achieve superior electrochemical properties. However, it is a formidable challenge to acquire an electrode material which keeps both amorphous phase and organized morphology via a simple preparation method. In a departure of other sophisticated methods, ball milling could easily introduce amorphous phase with unique merits such as more interstitial sites for rapid diffusion of Li ions, and more void spaces for accommodation of volume change than the crystalline phase. In our work, 3D hierarchical porous electrodes were designed and synthesized via KCl-assisted ball milling method. Owing to the unique merits including crosslinked 3D porous network, amorphous manganese vanadate buffer layer and numerous oxygen defects introduced during the KCl-assisted milling, the as-prepared electrode showed boosted electrochemical performance. The as-prepared electrodes delivered a capacity as high as 540.55 mAh g after 500 cycles at 2 A g with 98.78% capacity retention and 85.39% after 900 cycles. In brief, KCl-assisted ball milling provided a feasible and efficient approach to achieve 3D hierarchical porous electrodes, casting light on new approach of developing advanced electrode materials with the organized morphologies and amorphous phase.