The　methanol-product　oil　batching　transportation　based　on　the　mature　products　pipeline　network　is　currently　one　of　the　research　hotspots　in　the　pipeline　transportation　industry.　In　order　to　seek　effective　control　measures　for　reducing　the　mixing　volume　of　methanol　and　product　oil,　the　mixing　rules　of　methanol-product　oil　batching　transportation　was　explored.　By　referencing　existing　operation　experience　of　product　oil　pipelines,　a　batching　transportation　pipeline　model　of　methanol　and　product　oil　was　established.　The　mixing　rules　and　characteristics　of　the　batching　transportation　of　methanol　and　gasoline　in　horizontal　pipelines　were　analyzed　under　different　operating　states.　The　results　indicate　that　the　oil　density　variation　has　little　impact　on　the　mixing　process　of　methanol　and　gasoline.　As　oil　kinematic　viscosity　increases,　the　mixing　volume　of　methanol　and　gasoline　increases　linearly,　and　the　mixing　volume　of　the　gasoline　in　front　of　methanol　is　higher　than　that　of　the　methanol　in　front　of　gasoline.　As　velocity　increases,　the　mixing　volume　of　methanol　and　gasoline　significantly　decreases　firstly　and　then　levels　off.　The　velocity　influence　on　the　mixing　volume　gradually　weakens　when　it　exceeds　1.　4　m/s.　As　the　pipeline　length　increases,　the　mixing　volume　of　methanol　and　gasoline　significantly　increases　firstly　and　then　levels　off.　The　trend　of　mixing　length　remains　basically　unchanged　with　the　transporting　distance　variation.　The　results　using　the　model　in　this　study　is　close　to　the　actual　mixing　process　of　methanol　and　product　oil,　and　the　results　of　the　classic　Austin　empirical　formula　are　higher　than　the　actual　value.　The　simulation　results　can　provide　a　theoretical　basis　and　reference　for　the　design,　operation,　and　maintenance　of　the　future　methanol-product　oil　batching　transportation　pipelines.　©　2025　Editorial　Office　of　Chemical　Engineering　(China).　All　rights　reserved.