Objective To investigate the effect of self-made portable negative pressure drainage device on wound repair in stage Ⅲ-Ⅳ pressure injury. Methods A total of 62 patients with stage III-IV pressure injury admitted to our hospital from April 2020 to November 2022 were selected as the research objects. They were divided into control group and observation group by random number table method, with 31 cases in each group. The control group was treated with wet healing technology, and the observation group was treated with self-made portable negative pressure drainage device on the basis of the control group. The repair effect, clinical related indicators and nursing satisfaction were compared between the two groups. Results The total effective rate of repair in the observation group was higher than that in the control group (P