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Biosphere stability is mainly determined by soil contamination rate,ability to perform ecologic functions.At present to assess degraded soils ecologic-biochemical condition the following indices are applied:· physical-chemical indices of soils contaminants resistance (cationic exchange capacity,soil buffer capacity towards acids and heavy metals (HM),active and hydrolytic acidity) · biological indices of soils contaminants resistance (soil ferments activity,CO2 isolation intensity,soil organisms total quantity) Hereby its necessary to take into consideration that each of the soil condition ecologic-biochemical indices responds differently to the same anthropogenic factor.The presented paper is dedicated to the most priority soil condition ecologic-biochemical indices ascertainment under the conditions of HM contamination.During the experiment various levels of soil contamination have been modeled.HM combined introduction into air-dry soil samples with the mass of 2 kg as soluble salts (ZnSO4×7H2O,CdSO4×H2O,NiSO4×7H2O,CuSO4×5H2O,CrCl3×6H2O) has been performed.The variants without HM introduction served as the controlling ones.The soil contamination summary indices (Zc) have been calculated for each variant.In the controlling variant Zc amounted 1,49.After HM introduction Zc in the variant №1 it amounted 38,50,in variant №2-79,49,in variant №3-131,49.One of the physical-chemical indices of HM soil resistance is buffer capacity towards acids.The assessment of soil buffer capacity towards acids has been defined according to pH change in the water extraction after adding of 1 mmol of chlorine hydrogen acid for 100 g of air-dry soil.Water extraction pH measurements have been carried out by ion-metric method.Initial soil and soil in variant №1 were characterized by the average level of buffer capacity towards acids,but for soil in variants №2 and №3 it was low.When Zc increased,active acidity also increased (prH2o decreased).Acidity increase is mainly connected with HM ions capacity to exchange interaction with soil-absorption complex,which results in iota H+ displacement into soil solution.Besides HM sulphates are hydrolytically acid salts,and in the hydrolysis process additional amount of H+ ions is isolated into the soil.Soil "breathing" is the most commonly used index of soil biologic activity.Soil breathing intensity has been determined by Rowell method.With the increase of Zc,CO2 isolation intensity decreased,that is connected with the microorganisms live activity repression due to HM toxic impact Contamination rate influence for biologic processes in soil has been defined by biologic processes activity deviation from control according to ecological standards.It has been stated that the introduced HM doses in any experiment variants affected soil micro-biocenosis condition extremely negatively and the greatest biological activity processes deviation from control is revealed in experiment variant №3 (84,59%).The conclusion is as follows the increased HM doses introduction into the soil in the first rate affected soil biological activity negatively,and the influence for soil physical-chemical parameters was less considerable.Hence biological factors are more perceptible for the ecologic-biochemical assessment of soil condition with high level of HM contamination.