A heavy metal cadmium deactivator for activating the activity of sulfur-reducing bacteria in rice field soil, and an application thereof. The deactivator is constituted by electron shuttles alone or electron shuttles and electron donors, but cannot be constituted by electron donors alone. The mass ratio of the electron donors to the electron shuttles is (1:3)-(1:8). Also, a heavy metal cadmium deactivating method for activating the activity of microorganisms in rice field soil, such as sulfur-reducing bacteria. By applying the functional deactivator to rice field soil, the activity of microorganisms, such as sulfur-reducing bacteria, can be activated, thereby accelerating the reduction process of sulfur and iron in soil to facilitate the fixation of cadmium； cadmium adsorption and accumulation in rice is reduced to achieve secure production in fields moderately or lightly polluted by cadmium.
