The invention relates to a rural small well water defluoridation device and an application method thereof, and belongs to the technical field of water treatment. The device is placed at the mouth of awell, well water is connected with a small electric pump through a pipeline, the small electric pump pumps the well water into a defluoridation pretreatment part, the well water is treated by a pretreatment filter element, then is filtered through a filter screen and finally enters a defluoridation part, and the well water is defluorinated by a defluoridation filter element in the defluoridationpart, then is filtered by a filter screen, enters a water storage box, and is finally discharged through a faucet. The device has a simple structure, and only the small electric pump consumes energy,so the device can be applied in a remote region, is easy to operate, and is not artificially controlled, and the electric pump is turned on when water is needed. Materials used in the invention mainlyare activated alumina and bone black, the two materials have low prices, a good defluoridation effect, can be easily obtained in remote rural regions, and can be replaced even in remote regions, so the application range of the device is expanded.