Abstract: In order to study effect on electromagnetic field in enclosure affected by penetrating conducting and its circuit, different models of penetrating and its circuit were established. Electromagnetic simulation software CST was used to do simulation. Experimental system was set up with a GTEM chamber, a vector network analyzer, a power amplifier and an ETS electric field probe to verify simulation results. Laws of influence on electromagnetic field in enclosure by penetrating conductor coupling and its terminal load effect were revealed. The results show that electromagnetic field in enclosure is affected by the combination of penetrating conductor resonance and enclosure resonance. Electric field strength got extremum at resonant frequency. Shielding effectiveness curve of penetrating conductor open at two terminals was close to the curve of penetrating conductor loading but not grounding model. Electric field of penetrating conductor loading grounding directly was significantly lower while resonant frequency was reduced. Changing laws of penetrating conductor loading floating grounding was similar to model of penetrating conductor loading but not grounding in low frequency and similar to model of penetrating conductor loading grounding directly in high frequency. The value of resistance and capacity at terminal of penetrating conductor can also affect electric field.