Background: Overhydration (OH) is a well-recognized problem in peritoneal dialysis (PD) patients and is an independent risk factor of mortality in this patient population. Achieving normohydration remains an important issue in dialysis therapy. The present study tries to compare clinical signs and find the optimal range for PD patients in China. Methods: A new bioimpedance spectroscopy device [body composition monitor (BCM)], which allows quantitative determination of how much the hydration status deviates from normal ranges (ΔHS), was selected. Blood pressure and ΔHS were analyzed in 92 PD patients from 1 dialysis center and compared with a matched healthy population (n = 45). Statistical analysis was performed using SPSS software, version 16.0 (SPSS Inc., Chicago, Ill., USA). Results: We took different OH values as cutoff thresholds; predictive accuracy was evaluated with sensitivity and specificity, and a receiver-operating characteristics curve and Youden’s index were adopted. Conclusion: Our data suggest that 2.0 liters is a reasonable cutoff value for ΔHS. This represents an important step towards a more objective choice of strategies for the optimal treatment of hypertension and fluid overload.