Abstract: The thermal characteristics for the flow through the annulus with inner finned tube under stationary and rotating conditions are experimentally investigated. The experiments are carried out using both unfinned and finned tubes at different rotating speeds range from 0 to 400 rpm. The effect of fins number and its heights are studied for the straight fins which used with inner pipe. The Reynolds number ranged from 3x104 to 9x104, while Taylor number ranged from 3x106 to 11x106. The results showed an increase of the heat transfer coefficient more than six times for the height of 30 mm and rotational speeds of 400 rpm at Re = 6x104, compared to the case for plain stationary pipe. The rotational speed revealed no effect on the efficiency and effectiveness of the fin. Correlation for Nusslet number and the overall efficiency are obtained.