Abstract: The low-frequency radio spectrometer carried by Chang'E-4 lander has successfully carried out observation. The observational data are continuously sent back to the ground data center monthly. After certain pretreatment, the 2C level spectrum data is released to scientific teams. The main purpose of this article is to evaluate whether this level of data meets the requirements for detecting the sky-averaged 21 cm global spectrum of the cosmic dark ages. We make a long-term integration of the 2C level data, and simulate the reception of the Galactic foreground radio radiation by the lander. Through the comparison and analysis of the two sets of data, we find that the 2C data has been reduced by 40-50 dB, which almost does not contain the far-field radiation signal of the Galactic foreground. Such a large reduction will affect the detection ability of the payload for the dark ages.