Objective To construct a symptom network during chemotherapy in adult patients with hematological tumors, and to identify the core symptoms and the impact of core symptoms on quality of life. Methods A total of 400 patients with hematological tumors were easily selected and investigated using a self-made demographic questionnaire, the Chinese version of the M.D. Anderson Symptom Inventory, and the 12-Item Short Form Health Survey (SF-12). R software was used to build symptom networks, analyze central indicators, and identify core symptoms. Univariate analysis and stratified regression analysis were conducted to explore the effect of core symptoms on the quality of life of adult patients with hematological tumors. Results The core symptom of adult patients with hematological tumors was distress. The most common symptoms were fatigue, dry mouth, and disturbed sleep. The most serious symptoms were fatigue, sleep disturbance, decreased appetite and distress. In the symptom network,distress was a symptom with the highest node strength(rs=1.235 7); fatigue was a symptom with the highest node closeness and node betweenness(rc=0.008 7, rb=30.000 0). Stratified regression analyses showed that distress and fatigue explained 31.5% of the variations in the total score in the physical domain after controlling for the demographic variables, and 31.5% of the variations in the total score in the psychological domain after controlling for demographic variables. Conclusion The core symptom in adult patients with hematological tumors during chemotherapy is distress; fatigue is at the center of the symptom network and has a high degree of proximity to other symptoms. Nurses can develop interventions to improve the effectiveness of symptom management in adult patients with hematological tumors by targeting distress and fatigue