Conducted emission measurements has more links，leads to measurement uncertainty assessment of conducted emission is more complex. In this paper, on the basis of analyzed power line conducted emission measurements from 25 Hz to 10 kHz (CE101) of uncertainty sources, taking airborne electronic equipment as test equipment, studied uncertainty methods of CE101. Firstly, introduced the measurement principle of CE101, on the basis of analyzed the measurement principle, determine the measurement activities as the main uncertainty source is measurement repeatability, instrument’s measurement performance, impedance mismatch and measurement system’s structures, etc. Secondly, establish the mathematical model of measurement uncertainty, and accessed standard measurement uncertainty of each component. Finally, we calculated the expanded uncertainty of CE101 by GUM method. The results showed that, expanded measurement uncertainty of airborne electronic equipment’s conduction current is 2.7 dB. The results have a positive effect for development measuring system in construction of EMC laboratory, enhance the laboratory measurement capability and protect the quality of the measurement results.