The invention discloses a soil heavy metal stabilizing agent. The soil heavy metal stabilizing agent comprises activated attapulgite and a heavy metal compounding agent. The heavy metal compounding agent is combined with the activated attapulgite through hydrogen bonds or covalent bonds, so that soil heavy metal is adsorbed by the activated attapulgite and the heavy metal compounding agent cooperatively. The heavy metal compounding agent is one or more of 3-sulfydryl-2-butyl alcohol, 2-sulfydryl-3-butanone, and 8-sulfydryl menthone. The mass fraction of sulfydryl in the soil heavy metal stabilizing agent is 0.5%-10%, and the particle size of the sulfydryl is smaller than 150 micrometers. The invention further discloses a preparation method of the soil heavy metal stabilizing agent and the application of the soil heavy metal stabilizing agent in soil remediation. According to the soil heavy metal stabilizing agent and the preparation method and application thereof, the soil heavy metal stabilizing agent which is neutral in pH value, nontoxic and environmentally friendly is prepared, the heavy metal is stabilized in the soil, the mobility and the biological activity of the heavy metal are reduced, secondary pollution is avoided during soil remediation, and the applicability is higher in soil remediation engineering.