Obesity has become a fast growing epidemic in developing countries, as well as in some of the developing countries. Tea showed strong effect in reducing body fat and lowering blood sugar. Intragastric administration has the advantage of higher controllability and quantifiable compared with feeding. The diet-induced obese mice by intragastric administration need shorter time to show out weight loss effect. This article tested the effect of instant Pu-erh tea on weight loss in diet-induced obese (DIO) mice. The results demonstrated that instant Pu-erh tea was be able to reduce the mouse weight dose-dependently. Its effect is stronger than that of L-carnitine, a weight loss drug currently on the market. Instant Pu-erh tea also accelerated lipid metabolism and eased the high-fat diet-induced liver injury.