Biochar, the solid product obtained from pyrolysis of bio-organic materials under oxygen deficiency or oxygen limitation, has a great potential in carbon sequestration, pollution remediation and soil improvement. It has also proven to be effective in enhancing plant disease resistance. We reviewed here the effects of biochar on plant diseases control with focus on the underlying mechanism of biochar-mediated plant disease resistance. Biochar can enhance plant resistance and promote the plant growth by inducing plant systemic resistance, improving soil physical, chemical and biological properties, shifting soil microbial community structure, increasing the abundance and activity of beneficial microbial groups, and increasing adsorption of pathogens and toxic compounds. The efficacy of biochar in plant disease control might vary with biochar feedstocks, application rates, soil types and disease types. The present review highlights the need to explore the complex interactions among "Biochar-Soil-Plant-Pathogen" and decipher the molecular mechanisms of biochar-mediated plant disease resistance using omics approaches.