Low　power　capillary　discharge　based　pulsed　plasma　thrusters　(CDPPTs)　are　electrothermally　dominated　thrusters　and　they　have　aroused　renewed　interest　in　the　investigation　and　enhancement　of　the　basic　performance　for　the　application　of　micro/nano　satellites　recently.　Research　on　the　ignition　mechanism　of　a　CDPPT　has　been　conducted　to　provide　insight　into　the　optimization　of　the　structure　design　and　promotion　of　the　lifetime　performance.　It　has　been　found　that　the　electrical　parameters,　the　geometry　parameters,　and　the　cumulative　effect　of　discharge　jointly　determine　the　discharge　ignition　characteristics.　A　single　ignition　process　is　divided　into　the　breakdown　of　igniter　and　the　development　of　the　main　discharge,　while　the　results　show　that　the　jitter　of　the　ignition　delay　time　is　mainly　introduced　from　the　former.　Shorter　ignition　delay　time　and　lower　jitter　can　be　obtained　with　a　higher　ignition　energy　and　main　charging　voltage　or　a　shorter　and　narrower　cavity,　which　is　positively　correlated　to　the　electric　field　distribution　along　the　propellant　surface.　Moreover,　with　long　duration　experiments,　it　reveals　that　the　surface　deposits　and　morphology　of　propellant　and　igniter　are　the　dominant　factors　that　cause　the　dispersity　of　the　ignition　effect　and　main　discharge　characteristics.　Published　by　AIP　Publishing.