Based on a bibliometric analysis in combination with other information analysis methods, this paper compares the different evaluation results on the subject of "electric vehicles" drawn from Web of Science (WOS) and from Scopus. We came to the following conclusions after a careful comparison of these two databases. Firstly, both WOS and Scopus would provide some valid and unique evaluation indicators. Secondly, they showed similar results in terms of evaluating research performance of countries and research organizations involved in the targeted subject fields. In fact, both databases are good for discovering the research trend in general at the macroscopic level. Lastly, we ought to take the disciplinary characteristics, the extent of journal inclusion and resource selection criteria as well as inevitable data errors into full account in making recommendations to policy decision-makers.