The　entire　process　of　deflagration-to-detonation　transition　(DDT)　in　narrow　channels　with　thin　obstacle　configurations　is　studied　through　high-resolution　simulations.　The　results　show　that　the　confinement　and　disturbance　of　obstacles　promote　considerably　the　flame　acceleration　and　DDT.　There　exist　two　modes　of　DDT　associating　with　obstacle　spacing　S.　For　small　spacing　S,　the　flame　acceleration　depends　on　strong　confinement　and　jet　flow　between　obstacles;　eventually　DDT　occurs　due　to　early　burning　amplified　by　shocks　in　front　of　the　flame.　However,　for　large　spacing　S,　the　flame　acceleration　is　mainly　attributed　to　turbulence;　DDT　results　from　the　interaction　of　reflection　shock　with　turbulent　flame.　It　is　found　that　the　run-up　distance　of　DDT　in　the　obstructed　channels　shortens　significantly,　as　compared　with　that　in　the　smooth　channel.