The adsorption kinetics, adsorption thermodynamics and the effects of organic matter and ionic strength on the adsorption of sulfachlorpyridazine (SCP) by black soil were studied according to OECD guideline 106. The results showed that the equilibrium time of SCP adsorption by black soil was 12 h under the effect of acidification, the fitting constant (k₂) of adsorption rate of quasi two order kinetic equation was 216.275 5 mg/(g·h) for acidified black soil, higher than that of the control black soil, which was 15.722 2 mg/(g·h). The results of adsorption thermodynamics showed acidification significantly improved the binding capacity of SCP and soil, the adsorption capacity was negatively correlated with temperature. The adsorption free energy (ΔG) showed that the adsorption process was spontaneous reaction mainly by physical adsorption, but acidification increased |ΔG|, which made the system more stable and easier to spontaneous reaction. Adding organic matter increased the SCP adsorption more by the control black soil than acidified black soil. Adsorption capacity of SCP by black soil was decreased with the increase of Ca²⁺ concentration in background solution, which was attributed to the competition between SCP and Ca²⁺ under acidification.