Officials said they raids, intended to "purify the network environment," resulted in the arrest of 8,900 suspects, China's official Xinhua news agency reported Tuesday.
In one instance police shut down a fraudulent public relations operation that allegedly tried to extort money by threatening to post bad reviews of products and services, officials said.
Earlier operations against "harmful and illegal" elements online had tackled Internet cafes. The latest raids were aimed specifically at thieves and scammers, authorities said.
About 4,400 criminal cases were likely to result from the raids and arrests, police said.