In order to study ionospheric passive sounding method and technology, this paper realizes a new ionospheric passive sounding mode on the CADI platform. That is to say, this paper improves scan frequency receiving function of CADI's receiver, receives various space signals by using the receiver, extracts ionospheric characteristic parameters f0F2
and high frequency channel property parameters. The proposal and realization of the new passive sounding mode based on the ionospheric digital ionosonde for the first time not only alleviates the congestion problem of the ionospheric high frequency band, but also provides an economical and effective method for the ionosphere and high frequency channel monitoring. The paper will have an extended application perspective in the space environment monitoring and forecasting.