Objective To explore the trajectory of prognostic nutritional index changes in patients during the initial dialysis induction period analyze the influencing factors of different trajectories and explore the correlation between different trajectories and dialysis quality. Method 152 patients in the initial dialysis induction period admitted to the Fourth Affiliated Hospital of Nanjing Medical University from June 2023 to October 2024 were selected as the study objects by convenient sampling method. Basic information questionnaire and prognostic nutrition index were used to conduct questionnaire surveys at the first dialysis T1 1 week after dialysis T2 2 weeks after dialysis T3 and 1 month after dialysis T4 and specific dialysis quality indicators were used as data from one month of dialysis at T4 stage. The latent class growth model was used to identify the trajectories of prognostic nutritional index changes. Univariate and multivariate logistic regression analyses were conducted to analyze the influencing factors of different trajectories. Analysis of variance was used for pairwise comparisons to explore the relationship between different trajectories and dialysis quality. Result 148 valid questionnaires were recovered 95 men 64. 19% and 53 women 35. 81% . There were three different trajectories of nutritional indices in patients during the initial dialysis induction period with mean probabilities of 0. 962 0. 958 and 0. 968 respectively. The three trajectory categories were malnutrition improvement group 48. 7% nutritional plateauing group 27. 4% and malnutrition exacerbation group 23. 9% respectively. The different trajectory categories differed significantly in age P= 0. 022 marriage χ 2 = 11. 983 P= 0. 017 BMI χ 2 = 9. 856 P = 0. 043 and co-morbidities χ 2 = 10. 107 P = 0. 006 . The results of the quality of dialysis in patients in 1 month of initial dialysis showed that the rate of decrease in urea ranged from 55. 35% to 80. 24% with a mean 68. 25±6. 11 % urea clearance index 1. 26±0. 25 and β2-microglobulin 45. 27±3. 64 g / L. The results of two-by-two comparison showed that the rate of urea decrease and urea clearance index of patients in the nutritional smooth group were higher than that of the malnutrition improvement group P < 0. 01 and higher than that of the malnutrition exacerbation group P < 0. 01 and the β2 - microglobulin of the patients in the nutritional smooth group was lower than that of the malnutrition improvement group P < 0. 01 and lower than that of the malnutrition exacerbation group P < 0. 01 . Conclusion Different trajectories are affected by the combination of patients' own age marriage BMI and co-morbidities etc. Paying attention to patients in the initial dialysis induction period in the malnutrition exacerbation group and formulating a personalized nutritional intervention plan has positive significance in improving the quality of dialysis and prolonging the survival cycle.