Abstract: The multi-turn, small side coincident loop is used to meet the needs of probing depth and adjust the limited roadway space. There are blind zones as a result of turn-off time in TEM. The turn-off time depends on the side and equivalent areas of transmitter loop under certain conditions.The calculations show that the blind area is about 20m on the condition of 40turns and 2m×2m transmitter loop.And then the distances selection method between the near two detection points based on blind zone theory is proposed.“11points” advanced detection observing system is designed to adjust different conditions based on smoke ring effect, which varies with the coal/rock inclination.The loop layout angles are calculated to fit different coal/rock inclination, which makes the system have more important practical value and significance.