Teaching and research are essential functions of modern research universities, yet many studies have found that teaching often takes time away from research, which may have a negative impact on research performance. This article extends the concept of teaching by including research-oriented teaching in addition to traditional curriculum-based teaching. Using a sample of 917 science and engineering faculty members from 21 Chinese research universities, this study analyses the impact of the two modes of teaching on faculty members' research performance. The results show that faculty members in research universities devote more time to research-oriented teaching than to curriculum-based teaching. Time spent on curriculum-based teaching has a significant negative relationship with research output, while time on research-oriented teaching promotes faculty members' research productivity and research excellence. The study also found heterogeneity in the effect of teaching time on research performance across different groups. The negative impact of curriculum-based teaching on research was only observed in the group of assistant professors. The positive effect of research-oriented teaching on research is significant among associate professors and male faculty members. Based on the findings, we put forward policy implications for faculty teaching management and research evaluation systems to facilitate the integration of teaching and research.