The tube bundle of plate finned tubes are often arranged in staggered banks,while in-line banks are rarely applied.Generally,the coefficients of heat transfer and resistance of staggered banks are higher than that of in-line banks.However,the coefficient of resistance of plate finned tubes of in-line banks is much lower than that of staggered banks,so,in some cases with restricted resistance,plate finned tubes of in-line banks could be adopted.The experimental results concerning heat transfer and resistance of the plate finned tubes of in-line banks with some special sizes are presented.