〔Abstract〕 Objective To investigate the clinical characteristics and prognosis of acute myeloid leukemia(AML) patients withPTPN11gene mutation. Methods Total 115 adult AML patients who underwent initial diagnosis, treatment, and second-generation sequencing(NGS) detecting at hospital were recruited in this study. Clinical data included disease characteristics, treatment efficacy, long-term prognosis, immune cell subpopulations, and leukemia stem cells were collected to analyze the clinical characteristics and prognosis of AML patients withPTPN11gene mutation. Results PTPN11gene mutation rate in newly diagnosed adult AML was 9.57%, and the mutation site mainly occurred in exon 3 region with all mutation type being point mutation. Compared withPTPN11wild-type group,PTPN11gene mutation group had a higher early mortality rate(18.18%vs4.00%,P=0.048), a lower complete response rate(33.33%vs67.71%,P=0.039), a higher recurrence rate(83.33%vs42.31%,P=0.043), a shorter median overall survival time(9 monthsvs20 months,P=0.026), a lower proportion of effector T cells[(1.39±0.12)%vs(3.56±0.46)%,P=0.038], and a higher proportion of leukemia stem cells[(13.82±3.66)%vs(3.87±1.40)%,P=0.021]. Conclusion PTPN11gene mutation is a poor prognostic marker for AML. Those patients have a high early mortality rate, low complete remission rate, high recurrence rate, short median overall survival time, a low proportion of effector T cells, and a high proportion of leukemia stem cells.