Electrolyte transistor including a gate structure, two sources/drains, an electrolyte layer and a buried conductive layer is provided. The gate structure including a gate dielectric layer and a gate is located above a substrate. The two sources/drains are separated from each other and located above the substrate on each side the gate structure. The electrolyte layer is located between and contacts the two sources/drains, and located between and contacts the gate structure and the substrate. The buried conductive layer is located between the electrolyte layer and the substrate. The electrolyte layer between the two sources/drains includes a channel. The conductivity of the electrolyte layer between the two sources/drains is changed by a redox reaction, so as to turn on or turn off the channel.