The quality of ostomy directly affects the stoma patient's quality of life. This study investigated the application of a moldable skin barrier in the self-care of elderly stoma patients after colostomy for colorectal cancer. A total of 104 elderly stoma patients (65–79 years) who underwent colostomy because of colorectal cancer were randomly divided into an experimental group (56 cases) receiving a moldable skin barrier and a control group (48 cases) receiving a conventional skin barrier. The information on peristomal irritant dermatitis occurrence, the satisfaction of self-care, and related care costs were collected 1 month after patients were discharged from the hospital. The overall incidence of irritant dermatitis was significantly lower (p = .01), the self-care satisfaction score was significantly higher (p = .02), and the cost for leakage-proof cream (p < .001) was significantly lower in the experimental group than in the control group. In contrast, no significant differences in the cost of ostomy equipment and the barrier replacement interval were observed. In conclusion, a moldable skin barrier can reduce the incidence of irritant dermatitis in elderly stoma patients, improve their self-care satisfaction, and reduce the cost of leakage-proof cream use compared with the conventional stoma skin barrier.