Many oilfields are in the development stage at present, it has important significance to monitor oil and gas reservoirs using time-lapse electromagnetic. Four continuous electromagnetic profiling (CEMP) lines with 199 stations have been acquired in the Sebei gas field. Remote reference is used to suppress noise during field data acquisition. Data format of 4 frequencies per octave is output to improve the resolution and information of the filed data. High precision two-dimensional magnetotelluric (MT) inversion is adopted to process the data. The inversion results show that, the resolution has been improved with high sampling rate of CEMP data and high precision processing method. It provides technical support for time-lapse MT monitoring. The high resistance characteristic is very clear shown in the inversion profiles of Sebei gas filed. It provides important basis for time-lapse MT monitoring oil and gas reservoir. The inversion results are consistent with the logging curves, and the predicted reservoir area and thickness are consistent with the known wells and the collected data.