The molecular communication via diffusion (MCvD) is one of the most promising molecular communication (MC) techniques to construct the nano-networks due to its advantages of good bio-compatibility and high energy efficiency. However, due to the diffusion nature of information molecules, the data rate of MCvD is slow and the inter-symbol interference (ISI) effect is quite severe which limits the development and application of MCvD. In this letter, an electric-field assisted MCvD (EF-MCvD) is proposed to mitigate the ISI effect and improve the date rate. The impacts of the electric field on the data rate and the bit error rate performance of the proposed scheme are investigated. The results demonstrate that, the proposed EF-MCvD scheme effectively suppresses the ISI effect and improves the data rate of the MCvD system.