The　growth　of　thin　amorphous　hydrogenated　carbon　films　(a-C:H)　on　diamond　(111)　surface　from　the　bombardment　of　CH2　radicals　is　studied　using　molecular　dynamics　simulations.　Structural　analysis　shows　that　the　local　structure　(e.g.,　the　first　coordination　number　of　C　atoms)　of　a-C:H　depends　critically　on　the　content　of　hydrogen.　The　increase　in　kinetic　energy　of　incident　radicals　leads　to　the　decrease　of　hydrogen　content,　which　subsequently　changes　the　proportion　of　sp(3)　bonded　C　atoms　in　a-C:H.