Biochar is obtained from the pyrolysis of raw materials under anoxic or anaerobic conditions, which is widely used in soil amelioration for its soil improving properties. This paper introduces the modification and preparation of different biochars, summarizes the effect of biochar addition on soil infiltration capacity, evaporation capacity, soil nutrients, soil microorganism, enzyme activity, and soil remediation. It is found that the effect of biochar on soil amelioration is mainly related to the original raw materials, preparation conditions, amount of biochar addition and the method of biochar addition. It is suggested that the future research should focus on the appropriate classification of all kinds of biochars and find out the optimum utilization method for each of them, so as to provide theoretical basis for the further promotion and utilization of biochars.