This invention disclosed a tangerine peel extract, which is obtained from tangerine peels as raw materials through supercritical CO2 extraction. Such tangerine peel extract contains a large amount of flavonoid and terpenoid compositions that can effectively regulate the functions of the spleen and stomach; and has the effect of weight loss. This invention also declares the preparation method of the above mentioned tangerine peel extract, which is simple in technique and highly efficient in extraction. This invention also further declares the application of the above mentioned tangerine peel extract in preparing the healthcare food, which possesses the function of weight loss.