A　novel　active　soft-switching　converter　is　presented　for　an　multi-transient　electromagnetic　method　(MTEM)　transmitter.　The　topology　and　operation　principle　of　the　MTEM　transmitter　are　introduced　in　detail.　Compared　with　the　conventional　converter,　the　proposed　converter　can　operate　in　passive,　single　active　and　dual　active　soft-switching　modes　to　achieve　zero　voltage　switch　over　the　entire　load　range,　and　the　output　power　is　greatly　expanded.　MTEM　transmitter　has　the　characteristics　of　large　output-power,　high-efficiency　and　strong-stability.　The　research　has　provided　a　solution　for　the　development　of　other　transmitters.　At　present,　a　50　kW　prototype　has　been　completed　and　achieves　1　000　V/50　A　output　in　the　field.　©　2019,　Shanghai　Jiao　Tong　University　Press.　All　right　reserved.