An encapsulated effusion after appendectomy may be due to a bacterial infection that creates an inflammatory pus buildup. Post-appendectomy encapsulated effusions are most often caused by infection. A common cause may be contamination of the appendix during surgery, especially perforated appendicitis, if the abdominal pus is not completely removed, there can be a bacterial infection, and at this time, the body resistance is strong, and the infection is confined to, and the encapsulated effusion can appear. The appearance of postoperative appendicitis encapsulated effusion can have a feeling of lower abdominal distension, anal distension, and the performance of urgency and heaviness. At this time, the nature of the effusion should be determined by various auxiliary examinations, such as ultrasonography, CT or puncture aspiration, for differential diagnosis and diagnosis. In addition, it cannot be ruled out whether it is an encapsulated effusion formed by postoperative exudate accumulation in the surrounding tissues, or fluid accumulation of other nature. Therefore, when an encapsulated effusion occurs after appendectomy, it is important to seek prompt medical attention and treatment under the guidance of a specialist.