The thermal conductivity of microporous nano plate and fiber board was measured by non steady hot-wire method at RT to 1000℃ temperature range,and the results were analyzed and explained by SEM micro morphology analysis and fluorescence spectrum composition analysis, combined with micro thermal conductivity mechanism.The results show that the thermal conductivity of the nano plate is in the range of 0.03 to 0.1W/(m·K), and the fiber board is 0.055 to 0.25W/(m·K),the thermal conductivity of the two materials both have an upward trend with increasing temperature,the difference is that the thermal conductivity of fiber board began to increase sharply after 300℃, while the nano plate started after 550℃.However,the overall trend of the nano plate was obviously slower than that of the fiber board,and the higher the temperature,the greater the difference.Analysis suggests that the nano-sized particles and internal pores are the key factors that lead to low thermal conductivity of nano plates.