Ankangite is a new mineral discovered in the Shiti barite deposit, Ankang County, Shaanxi Province, with approximate formula Ba1.2(Ti5.3 V2.8)8.1O16.One dimensional incommensurate modulated structure is found along its c-axis, and the wave vector is q=1/2.30 c*. Ankangite (its average structure) is isostructural with hollandite. Space group 14/m, a=10.139(4)A，b=2.961(2) A，Z=1 .The intensity data of the average structure were abtained on a CAD -4 diffractometer, and R=0.039 (535 independent reflections).Its Supercell is 14 times as large as its subcell. Space group P4/m, a=10.126(4)A，c=41.41 (2A，Z=14.8696 independent reflections, including main and satellite reflec- tions, were collected by RASA-II S type diffractometer (RIGAKU)，and R= 0.2157 (2353 observed reflections).The vacancies and displacement of Ba atoms were determined in square-prismatic tunnels. The determination indica- tes that the incommensurate modulation of ankangite is a combination of occupancy modulation and displacive modulation, and is a square wave modu- lation along c--axis.、