The utility model discloses an airtight space electric field measuring equipment, forward power amplifier, radio frequency filter, power supply circuit and color liquid crystal display including signal analysis monolithic controller, signal preamplifier, communication interface, debugging interface, data, signal preamplifier includes inductive transducer and two operational circuit, power amplifier, color liquid crystal display and two operational circuit are forwardded to signal analysis monolithic controller connecting communication interface, debugging interface, data respectively, and two operational circuit still connect inductive transducer. The utility model discloses an airtight space electric field measuring equipment can carry out wave form record ripples and time domain and frequency domain analysis to electromagnetic wave in the airtight space, and then judges assay through going in the airtight space cable fault location, the utility model discloses an airtight space electric field measuring equipment's utility model will play incomparable accuracy of other technological means and real -time with the location to judging of trouble in the cable channel.