Hydatid cyst is a serious parasitic infection in places, which people has a close contact with dogs or sheep. They may be found as an incidental findings during routine clinical examination or even followed by radiographic or ultrasonography evaluation. The disease becomes more complicated if rupture of the cysts occurs due to blunt trauma or spontaneously increases of intra-cystic pressure. Here, we reported a case of hydatid liver cyst that ruptured into the peritoneal cavity after blunt abdominal trauma.