Biochar has been demonstrated to have a high porosity, special surface properties, and chemical stability, which can significantly benefit the adsorption of organic and inorganic pollutants. However, some environmental stimuli such as salinity, drought, and heavy metal stress might influence biochar’s remediation efficiency largely. This chapter reviews the biochar adsorption software, modified methods, and application fields for soil and water pollutants under stressed conditions. We study the effects of soil, salinity, drought, and heavy metals on characteristics as well as ion exchange and adsorption capacity of biochar, revealing that the exchange-controlling technologies had been promoted as well as suppressed in the presence of these materials. The chapter then focuses on the potential of biochar to reduce heavy metal toxicity through ion exchange, complexation, and precipitation mechanisms. We report some of the recent technical contributions in biochar production processes (mainly based on chemical/physical modification principles) that may support to produce efficient biochar output even under hostile environments. We estimate and evaluate the capacity of biochar to improve fertility in soil systems through unwashable nutrient retention, but also consumed microbial population support even in unfavorable environments, focusing particularly on bio-film formation and resistance to adverse living conditions in per-genetic environment which cannot be suitably addressed by the traditional strategy based on humus. In addition, the issues about large-scale application of biochar and future research direction for enhancing the potential of biochar as sustainable remediation technology for degraded ecosystems are also discussed in this chapter.