In the present research the thermal properties of phenolic resin 2123-P mix-modified by nano-alumina are investigated. The nano-alumina employed in the research can be classified two kinds, one is treated by 1%wt. silane coupling agent KH-550 relative to the weight of alumina, and the other is commercial alumina untreated. DTA-TG results show the thermal stability and anti-weight loss ability of the mix-modified phenolic resin 2123-P with KH-550 treated alumina are increased relative to those of the pure 2123-P and those of the mix-modified 2123-P with commercial alumina, and the results are to be proved by the constant speed friction and wear tests. It can be observed from SEM that KH-550 treated nano-alumina particles are dispersed equably in phenolic resin.