Distribution of different metal pools and soil-solution partitioning models are able to provide information on different available fractions of heavy metals and their leaching capacity, thus are crucial for risk assessment and remediation practices. 30 historically contaminated arable soils with a wide range of soil properties and contaminated status were collected from Pb and Zn mining areas in Bijie City of Guizhou Province. 5 typical-type soils without apparent contamination (clean soils) were collected from Guizhou Province and were artificially spiked with CdSO₄ or Pb(NO₃)₂ to form single-contaminated soils with different Pb/Cd concentrations. After aging for 3 months, chemically reactive metal pools, operationally defined by 0.43 mol/L HNO₃, 0.1 mol/L HCl and 0.005 mol/L DTPA, and directly available metal pool, defined by 0.01 mol/L CaCl₂ extraction, were determined to assess Cd and Pb contamination and to establish soil-solution partitioning models by using extended-Freundlich type equations. Chemical extraction was selected to best indicate total metal contents in soils. Factors affecting soil-solution partitioning were discussed. Results indicated that the ratio of directly available Cd and Pb pools to their total contents in historically contaminated soils were 4 and 223 times, respectively, lower than those in artificially-spiked soils. However, total reactive metal pools in historically contaminated soils were larger than those in these artificially-spiked soils and posed a great potential risk for agricultural production and human health vie food chain. Freundlich type equations perfectly described the relationships between total metal content and reactive metal pool. 0.43 mol/L HNO₃ extraction was selected to best predict total metal content in arable soils and the percentage of variation explained reached up to 99% and was able to replace the total metal content to indicate soil contamination. pH dependent Freundlich type equations were also able to accurately predict directly available Cd (R²=0.90) and Pb (R²=0.81) concentrations. Total reactive Cd pool controlled Cd concentration in soil solution. Soil pH was always the most important factor affecting Cd and Pb bioavailability, but soil organic matter and available phosphorus should also be considered to improve model prediction of directly available Pb pool.