Wide-bandgap metal oxide semiconductor (MOS) nanofiber neuromorphic transistors (NFNTs) can be potentially used to construct low-power bio-inspired artificial circuits. However, the cation ratio of MOS used for NFNTs is mostly adopted without detailed reasons in literature. In this study, we have for the first time focused on systematically tuning the cation ratio of indium zinc oxide (InZnO)-based NFNTs, fabricated by a low-cost electrospinning technique combined with a facile nanofiber transfer process. These electrical-driven NFNTs based on double-cation InZnO nanofibers can greatly simplify experimental procedures. Among the cation ratios of InxZn1−xO (x = 0.6, 0.7, 0.8, 0.9), we found that NFNTs based on In0.7Zn0.3O exhibited the lowest excitatory postsynaptic currents and offered electrical benefits for low-power operations and synaptic function simulations. The rational tuning of MOS nanofiber composition opens the door for high-performance low-power NFNTs.