The invention relates to a single electrode regulated ion triode with a diverging /convergent nano channel structure. The single electrode regulated ion triode comprises a substrate, an upper cover plate, regulating electrodes, driving electrodes, an insulating layer, and liquid storage pools; one driving electrode, the insulating layer, one liquid storage pool, the substrate, the other liquid storage pool, the insulating layer, and the other driving electrode are arranged from the front to the back successively; one regulating electrode, the insulating layer, the substrate, the insulating layer, and the other regulating electrode are arranged from the left to the right successively; the upper end surface of the substrate is provided with a diverging /convergent nano channel with a width of nanometer scale, and the single electrode regulated ion triode is penetrated by the diverging /convergent nano channel from the front to the back; and the upper cover plate used for covering the diverging /convergent nano channel is arranged on the substrate. The invention also relates to a characteristic adjusting method of the single electrode regulated ion triode with a diverging /convergent nano channel structure. The single electrode regulated ion triode is simpler in structure, is lower in cost, and is more convenient to prepare; real-time regulating of triode breakover current can be realized; and application prospect is promising. The invention belongs to the technical field of ion triode.