The invention discloses a video live broadcast system facing to a set-top box and a PC of a mobile phone and a working method thereof and relates to the technical field of network multimedia television, the field of video transmission and the field of mobile phone communication, the system comprises a mobile phone as a video source of the video live broadcast system and a video server which is connected with a mobile phone antenna, wherein the mobile phone comprises a video acquisition unit, a mobile phone video encoding unit, an audio acquisition unit, an audio encoding unit, a writing unit,a mobile phone storage unit, an antenna transceiving unit and a deleting unit; and the video server comprises a network communication unit, a video decoding unit, an audio decoding unit, a data buffer unit, a server storage unit, an audio and video synchronization unit, a live broadcast command processing unit, a server video encoding unit, a server audio encoding unit, a live broadcast data transmitting unit and the like. The system and the working method thereof can realize the function of acquiring a video by applying the mobile phone and carrying out live broadcast facing to a variety of types of terminals, in particular to the set-top boxes through 3G wireless network, WIFI or GPRS wireless communication network.