As a kind of ultra-efficient thermal energy harvesting cell, thermal concentrator has recently attracted great attention from researchers. An analytical expression which describes the temperature distribution in the concentrator is deduced from the heat conduction equation and coordinate transformation relations. The expression is validated by numerical experiments based on COMSOL. Influence of the anisotropy due to cladding and device geometry on the performance of the thermal concentrator is analyzed. It is demonstrated that the greater the anisotropy, the better the thermal concentration effect. Besides, increasing the aspect ratio between the cladding and the core radius also gives rise to a better performance. Based on the temperature distribution relations between the core and the background region, we further explore a method to practically realize such a thermal concentrator by using naturally available materials. It is suggested that different levels of thermal concentration can be achieved by arranging alternately two isotropic conductivities along the azimuth direction and tuning their thermal localizations respectively.