Diffuse hemispheric glioma，H3 G34-mutant is a high -grade glioma，which is newly defined by WHO in 2021，and its hallmark is the H3F3A gene mutation by exchanging glycine at position 34 of histone H3.3 for arginine or valine. This subtype occurs primarily in children and young adults and is clinically rare，of which the pathogenesis remains unclear. Imaging manifestations are not typical，and it is easy to be misdiagnosed and missed in the early stage. The diagnosis depends on immunohistochemistry and molecular pathology. Surgery is essential when it comes to treatment，supplemented by the postoperative radiotherapy and chemotherapy. Unfortunately，the prognosis remains poor. Here we reviewed the related research progress of this subtype in order to improve clinicians’understanding of the disease.