Caroli's syndrome is a rare autosomal recessive hereditary disease. Here a case of Caroli's syndrome associated with medullary sponge kidney was reported. The patient was a 2-years and 10 months-old boy. He presented with hepatosplenomegaly. Fever, abdominal pain or jaundice was not found. The imaging examination showed intrahepatic bile duct dilation, splenomegaly, medullary sponge kidney and nephrocalcinosis. After introduction of the case, this paper reviewed the clinical characteristics, diagnosis and treatment of Caroli's syndrome.