The present invention discloses a SOI MOS device having BTS structure and manufacturing method thereof. The source region of the SOI MOS device comprises: two heavily doped N-type regions, a heavily doped P-type region formed between the two heavily doped N-type regions, a silicide formed above the heavily doped N-type regions and the heavily doped P-type region, and a shallow N-type region which is contact to the silicide; an ohmic contact is formed between the heavily doped P-type region and the silicide thereon to release the holes accumulated in body region of the SOI MOS device and eliminate floating body effects thereof without increasing the chip area and also overcome the disadvantages such as decreased effective channel width of the devices in the BTS structure of the prior art. The manufacturing method comprises steps of: forming a heavily doped P-type region via ion implantation, forming a metal layer above the source region and forming a silicide via the heat treatment between the metal layer and the Si underneath. The device in the present invention could be fabricated via simplified fabricating process with great compatibility with traditional CMOS technology.