Background: The prognostic value of serum time-averaged albumin (TA-Alb) and time-averaged globulin (TA-Glo) combination on the peritonitis in peritoneal dialysis (PD) patients is unknown. Methods: The patients who started PD treatment between July 2013 and 2018 were included. Serum Alb and globulin (Glo) were tested at baseline and monthly during follow-up. TA-Alb and TA-Glo were calculated until first peritonitis occurred or the end of the study. PD patients were divided into 4 groups based on the medians of TA-Alb and TA-Glo separately. Cox regression was conducted to identify the hazard ratios (HRs) of peritonitis among categorical groups. Results: Three hundred and sixty-three patients were included and among them 109 patients experienced first peritonitis. Peritonitis patients had lower baseline Alb, TA-Alb, and TA-Glo levels and ultrafiltration volume. Multivariate cox regression analysis revealed that TA-Alb, TA-Glo, and baseline Alb were significantly associated with first peritonitis. The highest HR existed in Group 1 with lower Alb and lower Glo (HR 4.57, 95% CI 2.36–8.87, p < 0.001) compared with Group 4 with higher Alb and higher Glo. Conclusion: Lower TA-Glo is an independent risk factor for the first peritonitis in PD patients. Combined with lower TA-Alb will increase the predictive effect than separate factor alone.