The Janus kinase/signal transducer and activator of transcription (JAK/STAT) pathway is active in both normal hematopoiesis and hematological malignancies. Moreover, Janus kinase-2 (JAK2) is the key hematopoietic kinase, and mutations together with single nucleotide polymorphisms (SNPs) of JAK2 have been thoroughly evaluated. In this study, we aimed to investigate whether the synonymous genetic polymorphism A830G in the JAK2 gene is associated with the treatment outcomes of Ara-C-based chemotherapy regimens in patients with acute myeloid leukemia (AML). A total of 152 patients with AML in a Chinese population were enrolled in our study. Peripheral blood samples drawn at the time of diagnosis were analyzed for the presence of JAK2 A830G by matrix assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF-MS). The results showed that frequencies of the AA genotype were higher in the group 40-60 years old, higher white blood cell (WBC) patient group, homoharringtonine and Ara-C (HA) regimen group, and good therapy response group, and patients with the GG genotype were significantly associated with a higher rate of early death. We conclude that the AA and GG genotypes of JAK2 A830G might be important markers for therapy outcomes of patients with AML in a Chinese population.