Abstract: Described are a low temperature plasma reaction device and a hydrogen sulfide decomposition method. The reaction device includes: a first cavity; a second cavity, the second cavity being embedded inside or outside the first cavity; an inner electrode, the inner electrode being arranged in the first cavity; an outer electrode; and a barrier dielectric arranged between the outer electrode and the inner electrode. The hydrogen sulfide decomposition method includes: implementing dielectric barrier discharge at the outer electrode and the inner electrode of the low temperature plasma reaction device, introducing a raw material gas containing hydrogen sulfide into the first cavity to implement a hydrogen sulfide decomposition method, and continuously introducing a thermally conductive medium into the second cavity in order to control the temperature of the first cavity of the low temperature plasma reaction device.