The electromagnetic induction relationship among gas insulated line(GIL) circuits is different from overhead conductors. The existence of GIL in the line affects the calculation results of induced voltage and current,thus impacting the selection of line grounding knife. The double-circuit overhead line on the same tower and the GIL hybrid UHV line are taken as examples to study the calculation of electromagnetic induction between loops. Firstly,the electrical parameters of GIL are calculated. The calculation formula of relationship between induced voltage and current of transmission line with GIL is analyzed theoretically. Secondly,the theoretical analysis results are verified by EMTP-ATP simulation,and the induced voltage and current change law of the GIL in the busbar position,in the middle of the line and without GIL are simulated separately,and the reason for the large magnitude of induced current when the GIL is in the middle of the line is analyzed. Finally,the influence of difference length proportion of GIL in line on the induced voltage and current is studied. The research results provide a theoretical calculation reference for the selection of ground switches on mixed lines with GIL.