Under the old SNTV electoral system, Taiwan's district legislators have an intensive motivation to pursue personal vote. To attain this goal, some legislators make more efforts on the activities of constituency service, while others make more efforts on the activities in the legislative process. In June 2005, Taiwan's electoral system for district legislators had reformed to a single member district plural system. In this article, I conducted quantitative and qualitative research methods and focus on district legislators from the Fifth to the Seventh Legislative Yuan (from February 2002 to January 2012) to explore whether legislators change their behavior because of the system reform. Research findings show: legislators under the new electoral system emphasized even more on constituency service. They spent more time and resources on constituency, and their attitudes toward constituency service were even more cautious. They not only conducted more casework, but also they conducted casework much more widely diversified. At the meantime, legislators did not ignore legislative work. Owing to the limitation of time and resources, legislators engaged in the legislative process strategically. They delegated legislative power to the administrative branch. They then modified those bills proposed by the administrative branch and proposed their own version of bills with only one or two articles. Sometimes, they might co-author the bills proposed by their colleagues to save time and resources. This legislative style had appeared under the old system. It was reinforced under the new system. Finally, if they had to make a choice between constituency service and legislative work, most legislators were inclined to the constituency service.