Ovarian chocolate cysts, or ovarian endometriosis cysts, are the most common form of endometriosis and can manifest as dysmenorrhea, menstrual abnormalities, and infertility, and should be diagnosed and treated with surgery as early as possible. It has the following clinical features: (1) About 80% of the ovaries are involved on one side and 50% are involved bilaterally. It is also known as chocolate cyst because of repeated bleeding of the ectopic endometrium in the ovary forming single or multiple cysts with dark brown mucousy old blood inside the cysts, resembling chocolate liquid. (2) Ultrasound features: the cysts have uneven wall thickness and separation within the cysts, and small dots of light are reflected within the cysts. （CA125 may be elevated, but generally does not exceed 200 U/mL. (4) The size of the cysts is mostly 5-6 cm. When the ovaries are involved bilaterally, the cysts on both sides come together in the middle of the pelvic cavity behind the uterus, forming a “pair of kisses”. “(5) Rupture and secondary rupture can occur. (5) Rupture, secondary infection and malignancy can occur. The incidence of malignancy is about 0.7%. Rupture of the cyst may cause severe pain in the lower abdomen and other acute abdominal manifestations, mostly occurring before and after menstruation, during strenuous exercise or sexual intercourse, requiring emergency medical attention. (6) Early diagnosis and treatment are advocated, and laparoscopic surgery is usually preferred.