Hollow-core　fiber　(HCF)　has　found　plenty　of　interdisciplinary　applications　in　areas　ranging　from　ultra-intense　pulse　delivery,　single-cycle　pulse　generation,　low　latency　optical　communication,　UV　light　sources,　mid-IR　gas　lasers　to　biochemical　sensing,　quantum　optics　and　mid-IR　to　Terahertz　waveguides.　These　applications　calls　for　better　performance　HCF,　especially　in　loss,　bandwidth　and　mode　quality.　Here　we　present　a　new　hollow-core　fiber　with　conjoined-tubes　in　the　cladding　and　a　negative-curvature　core　shape.　It　exhibits　a　minimum　transmission　loss　of　2　dB/km　at　1512　nm　and　a　＜16　dB/km　bandwidth　covering　the　O,　E,　S,　C,　L　telecom　bands.　The　debut　of　this　conjoined-tube　hollow-core　fiber,　with　combined　merits　of　ultralow　loss,　broad　bandwidth,　low　bending　loss,　high　mode　quality　and　simple　structure　heralds　a　new　opportunity　to　fully　unleash　the　potential　of　hollow-core　fiber　in　laser　and　telecommunication　related　applications.