To characterize soil available lead (A.Pb) and identify its key drivers in typical farmlands of Zhejiang Province, 3 713 topsoil samples were collected from a provincial long-term monitoring network spanning 2008-2021. Fourteen physicochemical indexes, including pH, soil organic matter (SOM), total nitrogen (TN), available nitrogen (AN), available phosphorus (AP), available potassium (AK), slowly available potassium (SAK), and available Fe, Mn, Cu, Zn, B, Mo, and Pb were determined. Spearman correlation analysis, robust regression (M-estimation), random forest (RF) modelling, and structural equation modelling (SEM) were integrated to quantitatively dissect the A.Pb and soil factor relationships. The results showed that: 1) A.Pb in the studied soils ranged from 0.5 to 109.0 mg/kg, with a coefficient of variation of 59.5%. A total of 95.3% of the samples fell below the screening value (100 mg/kg) for agricultural land soil pollution risk. 2) Across the full dataset and within classification scenarios of different soil-forming parent materials, subgroups, genera, and tillage practices, the shared factors associated with A.Pb, ranked by frequency of occurrence and importance, followed the order of available Cu (A.Cu)>available Mo (A.Mo)>available Fe (A.Fe)>available Mn (A.Mn)>available Zn (A.Zn)>available B (A.B)>AP. These factors were jointly mediated by SOM, AP, pH, and A.Cu, with the mediation intensity ranked as SOM>AP>A.Cu>pH. 3) The dominant regulatory factor diverged by scenario: SOM exerted the strongest control in the full dataset, the de-gleyic paddy soil subgroup, percogenic paddy soil subgroup, the diluvial silt-sand paddy soil genus, and single-cropping late-rice fields; AP was paramount in soils derived from fluvial-lacustrine sediments and in the blue-purple clayey paddy soil genus; pH was the leading driver in diluvial parent material soils; and A.Cu contributed the most in rice-rapeseed rotation fields. All of these relationships could be quantitatively described by multiple linear regression equations. This study furnishes a theoretical basis and technical parameters for the targeted remediation of Pb-contaminated cropland through soil-nutrient-based management.