This study numerically investigated the heat transfer enhancement of planar elastic tube bundle by flow induced vibration based on a two-way fluid structure interaction (FSI) model in,the range of inlet velocity 0.2-0.5 m/s. This two-way FSI calculation involved the unsteady, three-dimensional incompressible Navier-Stokes equation solved with finite volume approach and the dynamic equilibrium equation of tube bundle solved with finite element method combined with dynamic mesh scheme, which was verified by comparing with the published experimental results. Then the Nusselt number of the circumference of tube, local position, single tube and the overall tube bundle was presented. The performance evaluation criterion (PEC) was selected to study the heat transfer performance of planar elastic tube bundle. Results show that vibration frequency dominates the heat transfer enhancement at the local position near the mass-block. In the middle of tube bundle, vibration amplitude plays a significant role on heat transfer enhancement. Therefore, the average heat transfer enhancement of 12.97% and 4.58% at the middle two tubes is higher than that of 5.37% and 2.4% at the innermost and outermost tubes when the inlet velocity is 0.2 m/s and 0.5 m/s, respectively. In the range of inlet velocity 0.2-0.5 m/s, flow-induced vibration contributes to enhancing the heat transfer of planar elastic tube bundle at low inlet velocity, resulting in the heat transfer enhancement of 8.26%, 6.07%, 5.67% and 3.91% respectively. Compared to the mechanical vibration strengthening heat transfer technology, flow-induced vibration plays an advantage on energy conversion to improve heat transfer. PEC indicates that the higher inlet velocity is sometimes more acceptable to obtain a higher heat transfer coefficient in the industry production. (C) 2016 Elsevier Ltd. All rights reserved.