The diverticulum of the sigmoid colon is relatively common in the gastrointestinal tract, with the majority of cases being asymptomatic. A non-traumatic hemoperitoneum secondary to colonic diverticulum is very rare. Here, we report the case of a 35-year-old woman with hemoperitoneum caused by the bleeding of the serosal vessel of the sigmoid colon diverticulum. The bleeding focus was identified and ligated, and the diverticulum was invaginated laparoscopically. No blood vessel malformation was detected.