Four teams of inspectors are undertaking the probe into online pornography and fake news organisations across 11 Chinese provincial-level regions.
The month-long investigation, which will finish on May 26, aims to clean up "harmful" information online, targeting live-streaming, cloud service providers, mobile apps and websites circulating pornographic content, the National Office Against Pornographic and Illegal Publications said in a statement.
Inspectors are also tasked with looking into news blackmailing, fake news, journalists and media organisations, it said.