To　meet　the　demands　of　long　delay　time　in　second　level　for　small　size　delay　equipment,　Ansys　software　was　used　to　simulate　the　heat　transfer　of　delay　equipment　and　calculate　the　delay　time.　The　influence　of　working　conditions　on　performance　of　delay　equipment　was　investigated　for　comparison,　including　different　environmental　temperatures　and　different　thicknesses　of　insulating　sleeve.　The　results　show　that　the　speed　of　heat　transfer　at　the　central　point　of　the　clapboard　is　faster　than　that　at　the　edge　of　the　clapboard.　The　delay　time　of　the　equipment　with　an　insulating　sleeve　is　longer　than　that　without　insulating　sleeve,　while　the　inner　diameter　of　equipment　is　2　mm　and　its　thickness　of　the　insulating　sleeve　is　1　mm,　the　delay　composition　cannot　be　ignited.　The　lower　the　environmental　temperature　is,　the　longer　the　delay　time,　while　the　environmental　temperature　decreases　to　-30　°C　and　-40　°C,　the　heat　transferred　to　the　right　side　of　the　clapboard　is　much　less,　where　the　temperature　is　lower　than　the　decomposition　temperature　of　the　composition　so　that　the　delay　composition　cannot　be　ignited.