In　order　to　guide　the　application　of　hydrogen/methane　mixture　as　fuel，explosion　experiments　were　carried　out　using　a　cylindrical　closed　vessel　with　an　inner　diameter　and　length　of　300　mm.　The　effects　of　hydrogen　fraction（XH2）from　0　to　100%　and　equivalence　ratio（Φ）from　0.6　to　1.4　on　the　flame　evolution　and　explosion　pressure　were　investigated.　Meanwhile，CHEM-KIN　software　was　introduced　to　analyze　the　laminar　burning　velocity　and　sensitivity　coefficient　of　the　H2‐CH4‐air　premixed　gas.　The　results　showed　that，for　a　certain　Φ，the　maximum　explosion　pressure（pmax），the　maximum　pressure　rise　rate（（dp/dt）max），the　explosion　index（KG），and　the　laminar　burning　velocity　increased　monotonically　with　the　increase　of　XH2.　The　duration　to　reach　pmax　and（dp/dt）max　，named　tA　and　tB，respectively，decreased　gradually.　After　ignition，the　flame　surface　gradually　transformed　from　a　smooth　structure　to　a　honeycomb　flame　lattice　structure.　With　a　constant　Φ　and　an　increasing　XH2，the　duration　from　ignition　to　the　termination　of　the　explosion　decreased　dramatically.　Meanwhile，at　the　same　moment　the　flame　radius　increased　but　the　fold　on　the　flame　surface　increased.　The　simulation　results　showed　that　the　elementary　reactions　R35　and　R52　had　the　most　significant　influence　on　the　laminar　burning　velocity.　The　maximum　molar　fractions　of　the　key　radicals（H，O，and　OH）had　a　positive　correlation　with　the　laminar　burning　velocity，and　the　increase　of　XH2　lead　to　a　significant　increase　in　the　maximum　molar　fractions　of　the　key　radicals.　The　primitive　reactions　R38　and　R84　were　the　dominant　reactions　affecting　the　rate　of　production（ROP）of　key　radicals.　©　2025　Institute　of　Chemical　Materials,　China　Academy　of　Engineering　Physics.　All　rights　reserved.