Medical image transfer device, client terminal, transmission system and transmission method thereof

The invention provides a medical image transfer device, a client terminal, a transmission system and a transmission method thereof. The transfer device includes a connection establishing unit suitable for receiving a connection request sent by the client terminal and establishing connection with the client terminal according to the connection request; a first receiving unit suitable for receiving data request sent by the client terminal; a first sending unit suitable for sending a corresponding data acquiring request to a PACS server according to the data request; a second receiving unit suitable for receiving data returned according to the data acquiring request by the PACS server; and a second sending unit suitable for sending data received by the second receiving unit to the client terminal through the connection. By using the transfer device, a problem of timeout of connection with the client terminal can be relieved and a problem of network congestion caused by that the client terminal sends too many requests to the transfer device can be avoided.