This study investigates natural convection heat transfer from a vertical array of five elliptic cylinders numerically. The axis ratio of each cylinder changes in the range from 0.25 to 0.75.ANSYS18.0 is used to study a two-dimensional natural convection for Rayleigh numbers varying in range of 10³ to 10⁵.The effect of the axis ratio and center-to-center separation distance from 2 to 5 cylinder major axis are examined. The average Nusselt number of each individual cylinder and the array are investigated to describe the strength of heat transfer. As the separation distance increases, the average Nusselt number of the bottom cylinder in the array basically unchanged, and the average Nusselt number of downstream cylinder increases. The average Nusselt number of the array increases with increasing the Rayleigh number and cylinder spacing.