Abstract: Circuit resistance measurement is one of the main items during hand-over test and routine test of GIS. The objective of the test is to check electrical equipment installation quality and loop circuit integrity. With consideration of common GIS inner conductor connection model, influencing factors of main loop resistance and shortcomings of circuit resistance measurement, a qualitative location analysis method is proposed to detect defective circuit resistance of 500 kV GIS. The method uses three steps to narrow search area, locate the defect and find out defective reason which includes diagnostic test, circuit breaker gas chamber check and disassembling inspection of TA gas chamber and grounding switch.