An electronic device and an operation method thereof are provided. The electronic device includes a fixing element, a first main body and a second main body. The fixing element has a first arc-shaped groove, which passes through the fixing element. The second main body has a second arc-shaped groove and a first straight groove, wherein the second arc-shaped groove and the first straight groove are interconnected. The first main body has a first protrusion which passes through the first arc-shaped groove and lodges in the first straight groove. While the first protrusion is slid for a first predetermined distance from one end of the first straight groove, the first arc-shaped groove and the second arc-shaped groove are overlapped, so that the first protrusion is slid along the first arc-shaped groove which overlaps the second arc-shaped groove for driving the first main body.