If a hard package is found on the anus, ultrasound examination and anal finger examination are needed to clarify whether it is solid or cystic, superficial or deep, and whether it is connected to the rectal canal. If it is a superficial hard pack, it is mostly caused by secondary infection of perianal sebaceous cyst, which can be promoted by local disinfection and topical anti-inflammatory drops to promote its absorption. If it continues to increase in size after conservative treatment, it needs to be removed surgically. If the ultrasound clearly indicates that the mass is mixed with fluid echogenicity suggesting an abscess in the perianal area, abscesses can be drained by incision under the mark of ultrasound. If the ultrasound suggests a subcutaneous sinus tract that is connected to the rectal canal, it should be considered an anal fistula, except that the external opening does not break through the skin. In this case, sinus excision or incision of the external opening for adequate drainage and surgical treatment with hanging wires are required.