Rosemary essential oil was refined by molecular distillation technology and its physicochemical properties, volatile components and smoking quality were studied and compared with the unrefined rosemary essential oil. Results showed the refined rosemary essential oil had lighter color, purer fragrance, higher volatile component content, lower relative density, refractive index and acid value. The unrefined and refined rosemary essential oil had same variety but different relative contents of volatile components. In the refined rosemary essential oil, there were an upward trend in the relative contents of those volatile components had lower relative molecular weight and boiling point, and a downward trend in the relative contents of those volatile components had higher relative molecular weight and boiling point. In addition, the refined rosemary essential oil actively improved the sweet feeling and aroma of the tested cigarette and its suitable additive content was 0.002‰. When the addition contents of the two rosemary essential oils were both 0.002‰, the refined one had better smoking quality.