In　this　study,　the　thermal　decompositions　of　nickel　composite　fibers　(NCF)　under　different　atmospheres　of　flowing　nitrogen　and　air　were　investigated　by　XRD,　SEM-EDS,　and　TG-DTG　techniques.　Non-isothermal　studies　indicated　that　only　one　mass　loss　stage　occurred　over　the　temperature　regions　of　298-1,073　K　in　nitrogen.　The　mass　loss　was　from　the　decomposition.　But　after　this　decomposition,　nickel　was　oxidized　in　air,　when　the　temperature　was　high　enough.　In　nitrogen　media,　the　model-free　kinetic　analysis　method　was　applied　to　calculate　the　apparent　activation　energy　(E　(a))　and　pre-exponential　factor　(A).　The　method　combining　Satava-estak　equation　with　one　TG　curve　was　used　to　select　the　suitable　mechanism　functions　from　30　typical　kinetic　models.　Furthermore,　the　Coats-Redfern　method　was　used　to　study　the　NCF　decomposition　kinetics.　The　study　results　showed　that　the　decomposition　of　NCF　in　nitrogen　media　was　controlled　by　three-dimension　diffusion;　mechanism　function　was　the　anti-Jander　equation,　the　apparent　activation　energy　(E　(a))　and　the　pre-exponential　factor　(A)　were　172.3　kJ　mol(-1)　and　2.16　x　10(9)　s(-1),　respectively.　The　kinetic　equation　could　be　expressed　as　following:　d　alpha/dT　=　2.16　x　10(9)　/　beta　exp　(-20724.1/T)　{3/2(1+alpha)(2/3)[(1+alpha)(1/3)　-　1](-1)