Soil environmental benchmarks serve as the scientific cornerstone for establishing soil environmental quality standards. This cutting-edge field in soil environmental protection research encompasses interdisciplinary and foundational scientific issues such as soil environmental chemistry, environmental toxicology, biology, and risk assessment. Understanding and addressing these complex scientific challenges represent the forefront of soil environmental benchmark research. This article delves into several crucial scientific considerations that influence the toxicity thresholds of heavy metals in soil environmental benchmark research. These factors include non-biological elements, biological components, and the determination of dose-response relationships, encompassing the adjustment for soil aging and leaching factors, the modeling of low-dose stimulation effects, and methods for normalizing toxicity data. Furthermore, using Cd contamination in agricultural soil as a case study, this research establishes the Cd environmental benchmark (HC₅) for soils with varying properties. Equations based on cumulative distribution curves relating HC₅ values to soil properties are developed (e.g., LogHC₅=0.132pH+0.083OC+0.008CEC-1.448). The findings of this study are anticipated to offer valuable insights for the exploration of agricultural soil environmental indicators.