Abstract: The performances of pressure drop and heat transfer of six kinds of vortex generators in single-row wavy-finned flat tube of direct air-cooled condenser were numerically investigated,respectively.The considered vortex generators including rectangular winglet,delta winglet, trapezoidal winglet,cylindrical-shell rectangular winglet, cylindrical-shell delta winglet and cylindrical-shell trapezoidal winglet which have the same aspect ratio,trailing height,attack angle and placement in the flow channel with Reynolds number（Re） ranged from 600 to 1 800.The results show that rectangular winglet has the best heat transfer enhancement and the largest pressure drop with factors j and f are 14.27% and 18.32% higher than those of the flat tube for Re=1 729 respectively.The pressure drop and heat transfer of cylindricalshell trapezoidal winglet are much lower than the rectangular winglet by 4.7% and 1.5% at Re=1 729 respectively.With regard to the comprehensive factor （j/j 0）/（f/f 0） 1/3 ,cylindricalshell trapezoidal winglet has better overall performance.In addition,the effect of angle of inclination of cylindrical-shell trapezoidal winglet（0°,6°,12°,20°,24° and 26°） were evaluated and the results show that cylindrical-shell trapezoidal winglet with angle of inclination of 12° has the best heat transfer enhancement（4.29%~14.1% more than the flat tube）, lower pressure drop（7.5%~12.8% larger than the flat tube） and the comprehensive performance.This results from the optimal combination of the projectional area facing air flow with the length of inclined edge as well as the streamlined surface structure.