Abstract: In order to sustain prodigious anabolic needs, tumor cells need metabolic reprogramming that differs from untransformed somatic cells.Besides glucose metabolism in tumor, amino acid metabolism also plays an important role in tumor cell proliferation, migration, and invasion.It is an emerging trend in tumor energy metabolism research.The metabolic pathway of cysteine, a glucose-producing amino acid, involves a variety of enzymes and products, regulating physiological and pathological processes such as oxidative stress, energy metabolism, and autophagy.This article focuses on the exogenous transport and endogenous conversion pathways of cysteine in tumor cells, the various regulatory mechanisms of cysteine metabolism pathways on the occurrence and development of tumors, and the potential therapeutic targets based on cysteine metabolism pathways, which can provide a theoretical basis for clinical use of drugs against tumors.