Objective： To investigate the effect of black garlic on lubricating bowel and on the defecation function of constipation mice. Methods： Kunming mice were randomly divided into control group， model control group， positive control group and low， medium- and high-dose treatment groups. After continuous intragastric administration for 7 days， through applying small intestinal propelling test and defecation test in mice to observe the effect of the black garlic， the percentage of propellant in small intestine， the time of the first dejection， the dejection amount and weights in six hours and the stool shape were observed. Results： All the tested parameters differed significantly between each dose of black garlic infusion and either the model group or the positive control group. It could apparently improve the percentage of propellant in intestinal peristalsis， shorten the time of the first black dejection， increase feces amount and weights in six hours and improve the water content of mice feces. Conclusion： The black garlic had the laxative effect in constipation mice.