Time-interleaved　Analog-to-Digital　Converter　(TIADC)　is　an　efficient　way　to　achieve　higher　sampling　rates　for　medium-to-high　resolution　applications.　However,　the　performance　of　a　TIADC　suffers　from　mismatch　errors　among　the　sub-channels.　This　paper　presents　a　method　to　estimate　the　channel　mismatch　errors　using　the　sub-channels＇　output　data.　The　proposed　method　introduces　an　input　dependent　estimating　model　(IDEM)　based　on　an　equivalent　transfer　function　including　the　mismatch　errors　to　calculate　the　standard　deviation　of　the　mismatch　errors.　The　spurious-free　dynamic　range　(SFDR)　is　then　evaluated　by　applying　multi-tone　sinusoids　signal　to　input.　The　simulated　results　show　that　the　method　in　this　work　can　get　about　45dB　SFDR　enhancement.