【Objective】 The sedimentation characteristics of soil colloids are intricately linked to soil fertility and erosion resistance, with the critical coagulation concentration serving as a pivotal parameter for evaluating particle aggregation and dispersion. The rapid and accurate determination of this critical coagulation concentration holds significant importance in assessing soil quality. 【Method】 This study evaluated the critical coagulation concentrations of three types of particles: —montmorillonite, humic acid, and brown earth colloids, —by observing the trend in zeta potential variation on their surfaces. Through piecewise linear fitting, the feasibility of determining the critical coagulation concentration using the zeta potential method was verified in conjunction with dynamic laser light scattering. 【Result】 The findings reveal that: (1) The absolute value of zeta potential in each system decreased with increasing electrolyte concentration. This decline was rapid in the relatively low electrolyte concentration range but slowed down in the higher concentration range. (2) The critical coagulation concentration of montmorillonite and brown earth colloids on the charged surface in potassium and calcium ion systems, determined through piecewise fitting with electrolyte concentration changes, aligned with measurements from dynamic laser light scattering. (3) However, there was a significant difference between the critical coagulation concentration measured by the zeta potential and dynamic laser light scattering methods for humic acid colloid with variable charged surface in potassium and calcium systems. 【Conclusion】 For montmorillonite and brown earth colloidal particles with constant charged surfaces, the zeta potential method could be used to rapidly and accurately determine their critical coagulation concentrations. This method boasted simplicity, required minimal sample volume, and offered high efficiency. Conversely, for humic acid colloidal particles with variable charged surfaces, the zeta potential method failed to accurately assess the critical coagulation concentration.