Analogous to a solid-state semiconductor diode for regulating the flow of electrons/holes to one preferential direction, nanofluidic diodes are being developed to achieve the rectified ionic transport. Such rectification effect is of great importance due to its relevance to biological ion channels. Moreover, ionic diodes, together with ionic transistors represent the key building blocks for ionic circuits, mimicking voltage-gated ion channels in a variety of biological systems. Several nanofluidic platforms based on nanopores and nanochannels were reported to produce ionic current rectification. Nevertheless, it has not been possible to change the predefined rectifying properties obtained by these approaches once the devices are made. We here report a field effect reconfigurable ionic diode (FERD) by asymmetrically modulating the cation/anion ratios along the nanochannel. A key feature of our device 1is that it allows the post-fabrication reconfiguration of the diode functions, such as the forward/reverse directions as well as the rectification degrees. These results may lead to the creation of reconfigurable ionic circuits, an ionic counterpart of the electronic field-programmable gate array (FPGA).