The research on biochar has become a hot topic in recent time due to its potential application in agriculture, environmental protection and carbon abatement by the increasing of carbon sink in soils. The amelioration effects and mechanisms of biochars on acid soils in tropical and subtropical regions, the effects of biochar incorporation on soil fertility, nutrient availability and the growth and yields of crops are summarized in this article. The development trends in this area in the future are analyzed. This article is hoped useful for the amelioration and management of acid soils in tropical and subtropical regions.