The invention provides a preparation method of elastic conductive yarn. The preparation method comprises following steps: S1, conductive core spun yarn is prepared by ring spinning; a predetermined amount of rough fiber yarn is fed from a horn mouth on a ring spinning frame and is drafted by a drafting device, and then fiber fringings are obtained and are pressed by a first front roller port consisting of a front upper roller and front upper leather roller of the drafting device; meanwhile, conductive fiber filaments pass through a first tension bowl and a first guide roller and then are fed from the first front roller port and subjected to twisting and wrapping, and the conductive core spun yarn is prepared; S2, the elastic conductive yarn is prepared by ring spinning; elastic fiber filaments and the conductive core spun yarn obtained in S1 pass through the tension bowl and the guide roller correspondingly and then are fed from a second front roller port simultaneously and subjected to twisting and wrapping, and the elastic conductive yarn is obtained. According to the preparation method, large-scale production is easy to realize, and the prepared elastic conductive yarn has flexibility, draftability and excellent performance of guaranteeing unchanged resistance when deformation is produced, and is wide in application range.