The arrested man, Wang, had circulated unconfirmed reports of public assaults and baby trafficking through mobile messaging app WeChat, police in northwest China's Ningxia Hui Autonomous Region said today.
Wang, who is an employee of an Internet company in the city of Guyuan, will remain in police detention for five days, state-run Xinhua news agency reported.
The arrest was made after Chinese authorities last week tightened control over instant messaging services by issuing a new regulation targeting the country's 5.8 million public accounts on instant messaging services against spreading rumours and obscene material online.
More than 800 million people use instant messaging in China, making more than 20 billion posts every day.
The new rule is part of wider attempts to police cyberspace.
Similar regulations were passed in 2012 for microblogging service Sina Weibo, which now has more than 500 million registered users.
