Traditional orthogonal frequency division multiplexing (OFDM) bandwidth estimation scheme can not acquire accurate estimation results in low signal to noise ratio (SNR) over multi-path channels. Besides, it acquires a great mount of computation. To deal with these problems, a novel bandwidth estimation scheme for OFDM is proposed. Firstly, the power spectrum of OFDM is estimated by the Welch method. And then, the spectrum is decomposed into many intrinsic mode functions (IMFs) by empirical mode decomposition (EMD) and the suitable IMFs are chosen according to the thresholds to reconstruct the spectrum. After that, the positions of the maximum and the minimum of the impulse are extracted in the reconstructed spectrum, which are used as the beginning and the end of the spectrum. Finally, the statistical average of the computed bandwidth is used as the final bandwidth. Simulation results show that the proposed scheme has higher precision and lower computation in low SNR over multi-path channels.