Police have detained more than 1,500 people suspected of selling equipment used to cheat on exams as part of a nationwide crackdown.
The arrests were announced on Tuesday, just before millions of Chinese teenagers take the national college entrance exam, or gaokao.
"The clampdown is targeted at people who steal or sell exam content (questions and answers for State-level exams and other tests), as well as those who produce and sell cheating equipment," said a Ministry of Public Security statement.
Offenders face a punishment of up to two weeks in police detention and thousands of yuan in fines, police said.
More than 60,000 electronic devices were seized during the operation, including clear-plastic earphones, wireless signal receivers, and modified pens, watches, glasses and leather belts, which are all forbidden from being sold in China.
"Exam-related crimes have an extremely bad influence on society," ministry publicity official Zhang Hongqiang told China Daily. "Police will remain on high alert and work with the Ministry of Education to combat such crimes.
"Authorities will also set up service stations near exam venues, and strengthen public order and traffic management during examination periods."
He declined to say how long the crackdown, which involved the investigation of 20,000 stores, mostly in the nation's electronics markets, has been running.
However, the detentions follow reports in September by the ministries of health, education and human resources that the content of State-level exams was being leaked, including for the professional medical exam and the master's entrance exam.
This year's gaokao, arguably the most important test for Chinese students, will be held on Thursday and Friday.
Despite intensified efforts to fight exam-related crime, cheating devices are still easily found for sale online and in electronic markets nationwide.
Several traders at the large Huaqiang North Electronic Market in Shenzhen, Guangdong province, said business for the illegal devices has been good in recent days.
"Many consumers at the moment are junior or senior students, or even their parents," said a male trader, when contacted by a China Daily reporter posing as a customer on Tuesday.
"Most prefer to buy clear-plastic earphones," he said, adding they are seen as "more efficient" but cost about 850 yuan ($130).
A woman who runs a store close by said traders selling banned devices are being extra cautious at the moment due to the crackdown ahead of the gaokao, but added: "As long as there is market demand, and the customers pay a good price, we're willing to take a risk."
Li Guifang, deputy director of criminal investigations for the All China Lawyers Association, said it needs cooperation from authorities to cope with the rampant cheating found in the exams.
"We should intensify the management for the examination room order, and conduct monitoring for the exam venues. Meanwhile, it's necessary to invite relevant authorities for supervision, including top legislature and disciplinary inspection departments, in stead of only the education sectors.
"Once such crimes occur, the judicial organs should intervene in a timely manner, then bring the suspects into the judicial process depending on the circumstance of the crime, rather than the education department itself for investigation," he said.