25ml sewage water sample was mixed, centrifuge at 10,000rpm for 30 minutes. The supernatant was added NaCl to 0.5mol/L and mix with 10% PEG6000 at 4degreeC overnight; The solution was centrifuged at 8,000rpm for 31 minutes, and the precipitate obtained was enriched virus.  Virus nucleic acid were extracted by Tiangen viral RNA extraction kit.  Ribosomal RNA was removed, and the kit for removing G+ and G-bacterial rRNA was used by Ribo-Zero. After removing rRNA, the library was constructed by the TransNGS RNA-Seq Library Prep Kit for Illumina.