Abstract: 【Abstract】 Objective To explore the relationship between uncertainty in illness, coping style and emotion in young and middle-aged patients undergoing peritoneal dialysis (PD). Methods Demographic questionnaire, Mishel Uncertainty in Illness Scale-Adult (MUIS-A), Medical Coping Modes Questionnaire (MCMQ) and Profile Of Mood State-Short Form (POMS-SF) were used to analyze the correlations among illness uncertainty, coping style and emotion in 75 young and middle-aged PD patients. Results The mean score of uncertainty in illness of young and middle-aged PD patients was in the moderate level. The confrontation coping, avoidance coping and resignation coping affected the illness uncertainty of the patients (R=0.461, P＜0.01). The total mood, anger-hostility and confusion-bewilderment affected the illness uncertainty of the patients (R=0.939, P＜0.01). Conclusions There are significant correlations among uncertainty in illness, coping style and emotion in young and middle-aged PD patients. Medical personnel should pay attention to design care measures individually, instruct the patients to manage emotion and adopt effective coping style to decrease their uncertainty in illness and improve their quality of life.

Key words: Young and middle-aged, Peritoneal dialysis, Uncertainty in illness, Coping style, Emotion