The invention discloses an internal humiture monitoring device of a lightning arrester body. The monitoring device comprises a humiture sensor assembly, a wireless data reception device, a background server and a display terminal, wherein the humiture sensor assembly comprises an electric field shield screen, a humiture sensing element, an SHT2x humiture sensor processor, an STC11 micro control unit, a wireless emission module and a lithium cell used for supplying power for each module, the humiture sensing element is arranged in the electric field shield screen, and the electric field shield screen is arranged in an electrode chamber of a lightning arrester. The monitoring device is advantaged in that a main defect source of the lightning arrester is considered, in combination with the detection technology in the prior art, operation state monitoring on the lightning arrester is further reinforced, monitoring modes increase, equipment operation guarantee is enhanced, more intelligent transformer substation operation is realized, work efficiency of operation staff is substantially improved, the monitoring device can be applied to lightning arresters in all voltage grades, an application scope is wide, and the monitoring device has excellent market prospects and application values.