According to the 2022 European LeukemiaNet, all acute myeloid leukemia (AML) cases with FLT3-ITD mutations are now categorized as intermediate risk irrespective of the FLT3-ITD allelic ratio or concurrent presence of NPM1 mutation. However, whether other next-generation sequencing (NGS) comutation genes can add layers to FLT3-ITD and whether the poor outcomes of FLT3-ITD comutations can be overcome by haploidentical hematopoietic stem cell transplantation (haplo-HSCT) are unclear. This study aimed to investigate which comutations based on NGS at diagnosis affect the clinical prognosis of de novo AML patients with FLT3-ITD mutations and the effect of haplo-HSCT on comutations. We analyzed 95 de novo AML patients with FLT3-ITD mutations from January 2018 to August 2021 based on the NGS 99-gene platform. Forty-one other types of molecular mutations were detected. The most common cooccurring mutations were NPM1 (n = 43, 45.3%) and DNMT3A (n = 21, 22.1%). NPM1 mutation did not affect the clinical outcomes. Acute myeloid leukemia patients with FLT3-ITD and DNMT3A comutations had significantly worse 3-year Disease-free survival (DFS) (49.5% vs. 69.3%, P = 0.01) and Overall survival (OS) rates (61.1% vs. 69.8%, P = 0.54) than those without DNMT3A mutations, and survival was significantly more favorable after haplo-HSCT than that after chemotherapy (3-year DFS, 85.7% vs. 30.8%, P = 0.006; 3-year OS, 85.7% vs. 43.1%, p = 0.08). In multivariate analysis, DNMT3A mutation was a risk factor for DFS, while haplo-HSCT was a protective factor. In conclusion, DNMT3A mutation might be a poor prognostic factor in adult AML patients with FLT3-ITD mutations, and haplo-HSCT could overcome the poor prognosis of DNMT3A comutation.