Accurate　measurement　of　the　ionization　cross　section　of　the　target　atom　induced　by　collision　between　ions　and　atoms　is　of　great　significance　for　studying　the　atomic　shell　process　and　establishing　a　suitable　theoretical　model.　The　experimental　data　and　the　theoretical　models　mostly　concentrate　on　the　cases　in　the　low　energy　region　at　present.　Only　a　few　experimental　data　of　high　energy　region　are　reported　due　to　the　limitation　of　experimental　conditions.　Which　theory　is　more　suitable　to　describe　the　ionization　cross　section　of　the　inner　shell　of　the　target　atom　caused　by　the　high　energy　heavy　ions,　is　necessarily　studied　experimentally.　The　C6+　ions　provided　by　the　Heavy　Ion　Research　Facility　in　Lanzhou　Electron　Cooling　Storage　Ring,　are　used　to　bombard　the　Ni　target,　in　which　the　K-shell　X-ray　of　Ni　is　measured.　The　incident　energies　of　C6+　ions　are　165,　300,　350　and　430　MeV/u　respectively.　Through　analyzing　the　intensity　ratio　of　K-beta/K-alpha　X-ray　of　Ni,　it　is　found　that　the　influence　of　incident　energy　on　the　intensity　ratio　of　K-beta/K-alpha　X-ray　is　not　obvious.　The　intensity　ratios　of　this　experiment　are　greater　than　the　experimental　values　of　incident　proton　and　the　calculated　values　based　on　the　Hartree-Slater　theory,　which　may　be　caused　by　the　multiple-ionization　of　the　L　shell.　The　production　cross　sections　of　Ni　K-shell　X-ray　are　calculated　by　the　binary　encounter　approximation　(BEA)　model,　the　plane　wave　Born　approximation　(PWBA)　model　and　the　energy-loss　coulomb-repulsion　perturbed-stationary-state　relativistic　(ECPSSR)　theory　respectively,　which　are　compared　with　the　experimental　results　in　this　paper.　It　is　found　that　the　experimental　cross　section　increases　with　the　increasing　incident　energy,　which　is　consistent　with　the　trend　of　BEA　model　estimation,　but　the　experimental　value　is　obviously　lower　than　the　theoretical　value.　We　think　that　BEA　model　needs　to　be　modified　when　describing　the　ionization　process　in　the　high　energy　region.