Purpose This study was aimed to develop and conduct an Omaha system-based continuing nursing program for chronic kidney disease (CKD) patients undergoing peritoneal dialysis (PD) and to explore its effect on patients' nutritional status. Methods A randomized controlled trial was performed in a teaching hospital in China between June 2017 and July 2018. A total of 203 eligible patients were included and then randomly assigned to the study group (n = 101) or the control group (n = 102). In the study group, health education, treatments and procedures, case management, and surveillance based on the Omaha system were used. In the control group, only common outpatient nursing intervention was given to the patients. Changes in subjective global assessment (SGA), anthropometric measurements including body mass index (BMI), triceps skin-fold thickness (TSF), mid-arm muscle circumference (MAMC), and handgrip strength (HGS), and biochemical parameters (hemoglobin, albumin, pre-albumin, total cholesterol, and creatinine) were evaluated before the intervention and 6 months after the intervention and differences in measurements were analyzed. Results After intervention, the proportion of well-nourished patients in the study group was significantly improved from 6.19 to 29.90% (chi(2) = 18.441, P < 0.001), and after 6 months, this was higher in the study group than that in the control group (29.90% vs 9.28%, chi(2) = 13.090, P < 0.001). Also, mean TSF, MAMC, and HGS were significantly improved in the study group and after 6 months, these levels were higher in the study group than those in the control group (P < 0.05). In addition, levels of hemoglobin, albumin, and pre-albumin in patients in the study group were significantly increased and after 6 months, these levels were higher in the study group than those in the control group (P < 0.05). Conclusions The continuing nursing program based on the Omaha system improved patients' nutritional status and should be further examined in future studies.