Abstract: Due to the uncertainty of parameter design of the Moon-based radiometer, the characteristics of Moon-based Earth’s outgoing radiation at the top of the atmosphere were investigated. Based on the single-point observation geometry for a Moon-based platform, this paper analyzed observational characteristics and data of different Moon-based platforms’ positions on the lunar surface, and the observational sampling characteristics. The results indicate that the orbit of the Moon is with variable orbital inclination and variant observation distances from the Earth, and equipping a radiometer on the lunar surface can sample the whole Earth’s surface within one orbital period. In addition, the suggested dynamic range is from 5.50×10⁻² to 8.50×10⁻² W/m², its temporal sampling interval is no more than 4 hours, and the accumulative sampling period is one orbital period (27.3 days). The above results provide an important basis for the design of the Moon-based radiometer.