Researchers have recently become interested in utilizing biochar amendment as an organic approach to enhance soil quality and minimize the mobility of toxic metals (TMs), which can help grow TM-tolerant plant species in polluted areas. A pot experiment was conducted to examine the efficacy of bamboo biochar (BB) in reducing the phytotoxicity of four unique mine-contaminated soil types. According to a completely randomized design (CRD), in four replications on Brassica juncea, a five-level bamboo biochar treatment (0% Control, 2.5% BB, 5% BB, 7.5% BB, and 10% BB) was administered in naturally contaminated areas of Sarcheshmeh, Gol-Gohar, Chadormalu, and Anguran mines. The data show that Bamboo Biochar (BB) increased soil enzymatic activities (58%), reformed soil structure, including pH (7%) and electrical conductivity (EC) (51%), and decreased the availability of TMs (Zn (37%), Pb(34%), Cd(51%), Cu(34%)), preventing accumulation in roots (42%) and translocation to shoots (38%). The phytochelatin (79%), ascorbic acid (56%), glutathione contents (57%), and antioxidant (51%) and glyoxalase activities (71%) in B. juncea ultimately enhanced root-shoot dry biomass (44%) and overall tolerance to TMs in mine-polluted soil (43%). BB at 10% might be used as a reliable soil amendment and natural metal immobilization adsorbent in the soil, as well as a suitable option for reducing oxidative stress caused by TMs in B. juncea plants, which are strong phytoremediation candidates in polluted soils. Future research endeavors might aim to discover cost-effective, efficient, and natural substances that can enhance and diminish environmental toxicity, eliminate soil contamination caused by heavy metals, and ultimately enhance human well-beingKeywords: Biochar Application; Soil amendment; Plant stress tolerance; Toxic metal; Phytoremediation