The　operation　of　short-turn　buses　will　affect　the　operation　state　of　full-length　buses.　The　reliability　of　bus　operation　system　can　be　improved　by　properly　designing　a　short-turn　departure　strategy.　Given　the　operation　of　short-turn　buses,　a　bus　operation　state　model　was　established.　And　the　departure　strategy　was　designed　with　the　cumulative　sum　(CUSUM)　method.　In　addition,　based　on　the　real-time　IC　data　of　bus　No.　973　in　Beijing,　the　influence　of　different　short-turn　bus　departure　strategies　on　the　operation　state　of　full-length　buses　and　passenger＇s　average　waiting　time　were　studied　by　numerical　simulation　method.　The　simulation　results　show　that　the　bus　departure　strategy　developed　by　this　method　can　not　only　improve　the　bus　operation　reliability,　but　also　greatly　reduce　the　passenger＇s　average　waiting　time;　improper　departure　time　arrangement　have　a　negative　impact　on　the　operation　reliability　of　other　full-length　vehicles.　©　2019,　Editorial　Department,　Journal　of　South　China　University　of　Technology.　All　right　reserved.