The invention discloses a soil heavy metal passivant as well as preparation and use methods thereof and belongs to the technical field of soil conditioners. The soil heavy metal passivant is prepared from tea dregs through the steps of carrying out repeated immersion cleaning and treatment by using deionized water, then, drying at 45 DEG C, smashing and sieving by using a 1mm sieve. By using the use method, the soil heavy metal passivant disclosed by the invention can be used for effectively reducing the activity of heavy metals in soil and also effectively improving the nutrient state of the soil so as to achieve the effect of increasing the soil fertility; and the preparation and use methods are simple, available in materials, low in cost and environment-friendly, and wastes are effectively utilized.