The　ignition　module　is　the　start-up　of　the　pulsed　plasma　thrusters　(PPT),　in　which　the　high-voltage　pulse　transformer　is　the　most　important　component,　as　its　output　characteristics　can　affect　the　reliability　of　PPT　ignition.　This　article　discusses　the　influence　of　the　parasitic　parameters　of　the　high-voltage　pulse　transformer　on　the　output　pulse　waveform.　It　reveals　that　the　leakage　inductance　of　the　high-voltage　pulse　transformer　is　the　root　factor　affecting　the　output　voltage＇s　rise　time,　while　parasitic　capacitance　and　excitation　inductance　have　little　influence　and　can　be　ignored　in　most　real　applications.　The　smaller　the　leakage　inductance　of　the　high-voltage　pulse　transformer,　the　better　the　overall　performance　of　the　output　pulse　voltage　waveform.　The　toroidal　high-voltage　pulse　transformer＇s　leakage　inductance　mechanism　is　analyzed　based　on　the　electromagnetic　field　principle,　and　the　theoretical　calculation　model　of　leakage　inductance　is　established.　Furthermore,　the　high-voltage　pulse　transformer　optimization　guideline　is　proposed.　The　optimized　high-voltage　pulse　transformer　can　reduce　leakage　inductance　by　71.8%.　Finally,　the　experimental　results　verify　the　theoretical　analysis　to　be　correct　and　useful.