A testing method of fluorescence based soft X-ray absorption spectroscopy is proposed. The method overcomes the problem of low fluorescence yield in soft X-ray region and eliminates self-absorption effect of fluorescence, and the soft X-ray absorption near edge structures (S-XANES) of materials are obtained by partially fluorescence yield (PFY) mode. Through the PFY mode, the soft X-ray absorption near edge structures of the buried element in perovskite solar cells, the trace element of catalyst, and the wide bandgap semiconductor are investigated. Compared with the total electron yield mode (TEY), the developed PFY mode of S-XANES has the advantages in characterization of materials bulk property, insulating materials and samples with low concentration.