The ratio of high-density lipoprotein cholesterol to apolipoprotein A1 (HAR) is associated with all-cause mortality in nonchronic kidney disease patients, but its role in predicting all-cause mortality in patients undergoing peritoneal dialysis (PD) is still unclear. The purpose of this study was to investigate the relationship between HAR and all-cause mortality in patients with PD. The medical records of 1199 patients with PD from November 1, 2005, to August 31, 2019, were collected retrospectively. The main outcome was defined as all-cause mortality. The HAR was divided into three groups by X-tile software. The association between HAR and all-cause mortality was evaluated by Cox models. The Kaplan-Meier method was used for the survival curve. The median follow-up period was 35 months (interquartile range: 20-57 months), with a total of 326 deaths recorded. After multiple adjustments, the risk of all-cause mortality in the high HAR group was 1.96-fold higher than that in the low HAR group (hazard ratio: 1.96; 95% CI, 1.22 to 3.15; P = 0.005). The restricted cubic splines showed that the risk of all-cause mortality increased gradually when HAR was >0.37. In the stratified analysis, a high HAR was linked to a high risk of all-cause mortality in males, patients under 55 years old, and patients without diabetes or cardiovascular disease (CVD). This study suggests that HAR is independently related to all-cause mortality in PD patients, especially in males, patients under 55 years old, and patients without diabetes or CVD.