Police have investigated 7,400 cases of cybercrime, the Ministry of Public Security said in a statement on its website. It did not make clear over what period the arrests were made but referred to a case dating to last December.
China launched a six-month program last month called Cleaning the Internet.
"For the next step, the public security organs will continue to increase their investigation and crack down on cybercrimes," the ministry said. The campaign will focus on breaking major cases and destroying online criminal gangs, it added.
The sweep targeted websites providing "illegal and harmful information" as well as advertisements for pornography, explosives, firearms and gambling. The police said they investigated 66,000 websites in total.
China runs one of the world's most sophisticated online censorship mechanisms, known as the Great Firewall. Censors keep a tight grip on what may be published, particularly material that could undermine the ruling Communist Party.
In February, China's Internet watchdog said that, starting March 1, it would ban any Internet accounts that impersonate people or organizations and would enforce the requirement for people to use their real names when registering online accounts.