Abstract: A new correlation equations were conducted on heat transfer parameters of air-side in circular finned-tube heat exchangers of staggered and in line arrangement. A Nusselt number and Euler number correlation are derived. The effects of fin height, fin spacing, fin pitch, tube outside diameter, fin diameter, transverse tube pitch, longitudinal tube pitch and number of rows are reflected in the correlations. The study covered the range of Reynolds number (8×10³-5×10⁴). Number of bundles used in this correlation 56 staggered and 33 in line. A numerical solution based on (DGA V1.00) and Excel programs were used to find constants of correlation equations. Also, Tecplot program is used to draw curves of results. Results show maximum deviation are in Nusselt number and Euler number correlations (6, 18% for staggered and 10, 11% for in line), respectively in addition, the effect of fin spacing or fin height on Nusselt number and Euler number in one bundle (S1 staggered and I1 in line) are investigated. Results showed that in staggered bundle arrangement S1, the Nu number increased and Eu number decreased when the fin spacing increased and fin height decreased. While the effect of decreased fin spacing and increased fin height led to in increased Nu number and Eu number at bundle I1 in line arrangement.