Abstract: To investigate the effectiveness and mechanisms of remediating heavy metal-contaminated soil under different washing sequences, we selected soil highly contaminated with Cd, Pb, and Zn from a lead–zinc mining area in Yunnan Province as the test soil. Ethylenediaminetetraacetic acid (EDTA), ferric chloride (FeCl₃), and citric acid (CA) were employed as washing agents. The microstructure of the soil before and after washing was characterized through single-factor optimization, cyclic washing, washing sequential trials, and washing kinetics experiments, combined with X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FT-IR). The results showed that the optimal concentrations of EDTA, FeCl₃, and CA were 0.25 mol/L, 0.30 mol/L, and 0.30 mol/L, with optimal reaction times of 120 min, 120 min, and 180 min, and optimal liquid-to-solid ratios of 15∶1, 20∶1, and 20∶1, respectively. After six washing cycles, FeCl₃ exhibited markedly superior long-term removal capability for Cd, Zn, and Pb compared with EDTA and CA, achieving total removal rates of 87.35%, 42.40%, and 66.87%, respectively. Among various washing sequences, the FeCl₃→EDTA sequence demonstrated the highest removal performance for Cd and Pb. The major mineral composition and functional groups of the soil showed no significant changes after washing. Kinetic fitting indicated that the Elovich and two-constant equations provided a good description of the washing process, with desorption primarily dominated by heterogeneous diffusion. Overall, this study demonstrates that FeCl₃ holds greater potential for application in cyclic washing, and that optimizing the sequence of washing agents can achieve targeted and enhanced removal of heavy metals. The FeCl₃→EDTA washing sequence yields the optimal remediation performance, providing a theoretical basis and technical reference for chemical washing remediation of high-concentration heavy metal-contaminated soils in mining areas.