Protection device and preparation method thereof

The invention relates to the technical field of circuit protection, in particular to a protection device and a preparation method thereof, and the protection device comprises: a first overvoltage protection element and a second overvoltage protection element which are connected in series, wherein the difference between the protection threshold values of the first overvoltage protection element andthe second overvoltage protection element is within a preset range; a heat conduction part which is connected with at least one of the first overvoltage protection element and the second overvoltageprotection element; and pins which are respectively led out from the first overvoltage protection element and the second overvoltage protection element. Through the cooperative use of the two overvoltage protection elements, the loss of the protection function caused by the model selection problem of a single overvoltage protection element can be avoided; and the heat conduction part connected with at least one of the firs