This article reports sonographic characteristics of a ruptured corpus luteum with hemoperitoneum in 44 cases. Sonographic findings were classified and compared with laparotomy and pathology. From sonographic imaging, it was found that the ruptured corpus luteum cyst was pathognomonic. There was a good correlation between ultrasound findings and surgical results when bleeding was over 100 ml. The sonographic value in diagnosis of ruptured corpus luteum with hemoperitoneum is discussed in detail.