The down-flow tube reactor was used for biomass pyrolysis liquefaction and proved effective. In order to study the characteristics of heat transfer between ceramic balls and biomass chars, an improved experimental platform of down-flow tube was designed based on the former research. In addition, the former experimental material biomass particles were replaced by chars, and the result of experiment would be indicative to the industry application. Based on the heat exchange experiment among the ceramic balls at different temperature (50,60,70℃) and the air at room temperature, by the analysis of thermal equilibrium, the convective heat exchange coefficent between ceramic balls and the air was worked out and the value was about 600W/(m2?K). The result of heat transfer experiment between ceramic balls and chars shows that temperature in the vertical tube obeys linear rule as the edge effect is not considered. The leading way of heat transfer in the down-flow tube is the convective heat exchange. 