Biochar, with the characteristics of porosity structure, high capability of adsorption, and containing much nutrient elements and functional groups, is a new functional material which has been paid more and more attentions in the fields of environment and agricultural application. In the present article, the basic properties of biochar were briefly introduced, and the probability that biochar became a substitute for activated carbon in the future was proposed. The applications of biochar to remediate contaminated soil with organic contaminant such as TPHs, pesticide, PAHs, PCBs, and also the environmental risk of using biochar as soil addition were reviewed in the paper. The conclusion indicated that biochar has a great potential to remediate contaminated soils, but both its effect and environment impact deserve more studies.