Non-SMC Condensin I complex subunit G (NCAPG), a mitosis-associated chromosomal condensation protein, is related to sister chromatid appropriate separation during the condensation and fusion of chromosomes and responsible for the condensation and stabilization of chromosomes during meiosis and mitosis. Studies have shown that NCAPG is highly adjusted in a variety of cancers, and its related molecular mechanism affects tumor cell proliferation, invasion, metastasis, and apoptosis including hepatocellular carcinoma, prostate cancer, breast cancer, gastric cancer, gliomas, lung adenocarcinoma, colorectal cancer, ovarian cancer, and endometrial cancer. Clinically, the expression of NCAPG is strongly correlated with N-classification, M-classification, and clinical stage, and NCAPG is valuable for the prognosis of patients with lung adenocarcinoma. In addition, NCAPG can also reduce the sensitivity of tumor cells such as breast cancer to reduce the reaction of the original chemotherapy, so that tumor cells are drug-resistance. In summary, NCAPG can serve as a new diagnosis and treatment target for a variety of cancers, and is also a very promising prognostic marker. Therefore, this review summarizes the critical role of NCAPG in the diagnosis, treatment, and prognosis for various cancers, and the mechanism by which NCAPG plays its pivotal roles.