Abstract:In this paper, we introduce the improving method for the SNR of the thermal sensor. Taking the nitrogen element in coal as the carrier, the method of improving the accuracy of the measurement of the nitrogen content in coal by thermal conductivity sensor is studied..The problems existing in the measurement: thermal conductivity effects of temperature stability, the results of the test, stability of power and frequency selective characteristics of the filter circuit on test results of influence of reason analysis, and one by one were corresponding optimization methods and design improvement, finally through comparison of measuring the output signal of the nitrogen system, signal to noise ratio is greatly improved.