Objective Exploring the trajectories of nutritional risk index changes during chemotherapy in lymphoma patients analyzing the influencing factors of different trajectories and exploring their correlation with quality of life. Method A longitudinal survey of 210 patients with lymphoma was selected for the study. Latent category growth modeling and one-way analysis of variance and two-by - two comparisons were performed to analyze the data for testing. Result There were three different trajectories in the operative nutrition risk index of lymphoma patients. The three trajectory categories were C1 steady decline group 44. 1% C2 rapid decline group 27. 5% and C3 low level fluctuation group 28. 4% . There were significant differences in age χ 2 = 11. 584 P = 0. 003 BMI χ 2 = 19. 661 P < 0. 001 tumor stage χ 2 = 40. 237 P < 0. 001 and synchronous radiotherapy χ 2 = 7. 593 P = 0. 022 . The quality of life difference analysis results showed that the quality of life of patients in the stable decline group was higher than that in the rapid decline group P < 0. 01 and the low fluctuation group P < 0. 01 and the quality of life of patients in the rapid decline group was higher than that in the low fluctuation group P < 0. 05 . Conclusion Medical personnel pay attention to the assessment of the level of nutritional risk index during chemotherapy for lymphoma pay attention to the patients in the rapidly declining group and the low-level fluctuation group and provide timely and necessary nutritional interventions and support which is important for correcting the risk of malnutrition and improving the nutritional status of the patients in the later stages of their lives.