The invention discloses a
sodium ion sensor and a preparation method thereof. The
sodium ion sensor comprises a substrate, a first
sodium ion selection
electrode, a second sodium ion selection
electrode, a
solid electrolyte reference layer, a sodium
ion sensitive film, an insulating layer and a
salt bridge, wherein the first sodium ion selection
electrode comprises a first reaction electrode arranged on the substrate; the second sodium ion selection electrode comprises a second reaction electrode arranged on the substrate; the
solid electrolyte reference layer covers the first reaction electrode and the second reaction electrode; the sodium
ion sensitive film is arranged on the
solid electrolyte reference layer; the insulating layer is arranged on the sodium
ion sensitive film; a first opening and a second opening are formed in the insulating layer; the first opening is communicated with the sodium ion sensitive film to form a first reaction cavity; the second opening is communicated with the sodium ion sensitive film to form a second reaction cavity; the
salt bridge is arranged on the insulating layer; one end of the
salt bridge extends to the inside of the first reaction cavity; and the other end of the salt bridge extends to the inside of the second reaction cavity. Through the manner, the sodium
ion sensor disclosed by the invention can be miniaturized, so that the sodium
ion sensor is convenient to carry and convenient to operate.