A large number of studies on the metabolism of immune cells in anti-tumor response have been carried out in recent years. It is proved that metabolic reprogramming can determine the differentiation and functions of immune cells. Myeloid-derived suppressor cells (MDSCs) are a heterogeneous population of immunosuppressive cells in the tumor microenvironment (TME). They can significantly inhibit the anti-tumor response of T cells and play an important role in promoting tumor growth, metastasis, and invasion. This review summarizes the energy metabolic pathways of MDSCs in the TME, such as fatty acid oxidation (FAO), glycolysis, and amino acids (AAs) metabolism, and highlights the importance of metabolic reprogramming of MDSCs for its immunosuppressive functions.