Aim To explore the effect of niacin on reverse cholesterol transport in mice in vivo and the possible mechanism. Methods 14 C57BL/6 mouse were treated with ordinary diet and niacin in diet for 4 weeks, then the semice were injected intraperitoneally with 3 H-cholesterol-labeled and cholesterol-loaded raw 264.7 macrophages (0.5 mL/mice, the amount of cells achieve 5.0×106). After 24 h, feces were collected and analyzed the appearance of 3 H-tracer (as the percentage of the total injected counts). Reverse transcription polymerase chain reaction (RT-PCR) were used to evaluate ABCG5; CYP7α, LXRα mRNA of liver and ABCG5, LXRα mRNA of intestina expression. And the level of ABCG5, LXRα proteins of liver and intestina was analyzed by Western blot. Results It was observed that niacin increased reverse cholesterol transport by 21% in mice in vivo in contrast to the control (P<0.05). Niacin increated ABCG5; CYP7α, LXRα mRNA of liver and ABCG5, LXRα mRNA of intestina expression, while having the same effect on the expression of liver, and intestina, ABCG5 and LXRα protein. Conclusion These results suppose that niacin promtes reverse cholesterol transport by increasing ABCG5 and CYP7αexpression which is stimulated by LXRα.