Abstract: A potential barrier will be created due to various kinds of interface and defects existed in the material, which would lead to the impeding of the low energy carrier's transport, resulting in higher average carrier energy and lower active carrier density. This carrier filtering effects would cause the improvement of Seebeck coefficient and power factor with simultaneously decreasing of carriers thermal conductivity, and finally bring dramatically increasing of the thermoelectric figure-of-merit ZT. This paper briefly introduced the potential barrier filtering, and reviewed the progressing of this mechanism on theory and laboratory research. Based on these progressing, we proposed that the optimal barrier height should be determined first for this mechanism, and the tuning method of the barrier height aroused from the interfaces between the nano composites and the matrix material, or the grain boundaries, should be fully explored in future.