Abstract: Objective: To evaluate the causes of medical device related pressure ulcer under the Colostomy Stoma and implement interventions accordingly. Methods: Investigate the possible reasons of 10 patients with medical device related pressure ulcer between April 2014 and December 2015, and making nursing plans accordingly, then observe the effects. Results: The reasons for the 10 patients with pressure ulcer were as follows: all of them using belt and two-piece chassis; six patients using convex chassis for stoma retraction; and for another four patients whose stomas were in poor position, one patient's stoma was under the right upper quadrant costal margin, while the other three's were too low; four patients had comorbidities; and two patients had diabetes. After the intervention according to the pressure ulcer guidelines,all pressure ulcers were healed, with healing time of 5-67 d, and the average time was 24.8 d. Conclusions: Pressure ulcer under stoma chassis was related to belt. We should assess chassis conditions and belt wearing time as well as tightness. And we can stablize the chassis to prevent the curling of the edge. When the patient's stoma was not in the optimum position,the enterostomal therapist could use eccentric circle tailor the chassis. At the same time, choosing appropriate dressing to debridement according to the stage and area of the pressure ulcer to enhance healing.