Objective Malnutrition is closely related to the outcome of peritoneal dialysis patient. In the clinically stable patient, nPCR provides a valid estimate of protein intake. The present research was to evaluate the influence factors of nPCR and examine its predictive power of clinical outcomes in peritoneal dialysis patients. Methods A prospective observational cohort study was performed in 86 clinically stable peritoneal dialysis patients followed-up in hemodialysis center. The routine biochemical tests including albumin, prealbumin, glucose, lipid, calcium and phosphorus, and the levels of C-reaction protein (CRP) and interleukin-6 (IL-6) were estimated. The nPCR was calculated by Baxter PD Adquest, version 2.0 for Windows. The stepwise regression method was enrolled to estimate the independent parameters of nPCR. Patients were followed up for a mean±SD duration of (32±13) mo. Results The mean level of nPCR was 0.90·d)]. The level of nPCR was inversely related to age, and directly related to albumin and HDL. It was inversely related to the levels of CRP and IL-6. There were inverse correlations between nPCR and total Ccr, residual renal Ccr, total Kt/V and residual renal Kt/V. While the relationships between nPCR and peritoneal Ccr and peritoneal Kt/V were not significant. The multiple stepwise regression analysis showed the independent effect of total Kt/V on the level of nPCR. Patients in the lower tertiles of nPCR [＜0.82g/(kg·d)] were in higher risk of subsequent mortality. Conclusion A lower nPCR is associated with increased mortality. Dialysis adequacy has independent effect on the level of nPCR.