Abstract: A new downhole dynamic imaging transient electromagnetic instrument is designed. The transmitter of transient electromagnetic instrument adopts six field effect tubes to form a fast shutdown bridge. During the shutdown of transmitting current, the parasitic diode in the field length effect tube constructs a fast discharge circuit, which reduces the inductance effect of transmitting coil and greatly reduces the detection blind area; the transient electromagnetic receiver adopts dual channel signal processing circuit, dual AD acquisition at the same time, and the signal receiving range can reach more than 160 db through data splicing processing; the embedded industrial control function of Linux operating system can quickly analyze and process the data, and complete the data acquisition to the final apparent resistivity rapid imaging within 2 s.