She only was identified by her surname, Huang. She also is accused of sending a copy of the video to a former colleague surnamed Wang.
The 12-minute video first appeared on the Internet at the end of October under the title "Kappa Girl at Shanghai No. 1 Department Store's East Building." The title refers to the sportswear shop where Huang worked. She has been reportedly dismissed from her job.
It soon became a popular download, with thousands of people downloading it in the last month, the bureau said.
Police officials said that Huang set up the blog to profit from her notoriety by offering advertising space and interviews in exchange for cash. In the blog, Huang reportedly said she would give interviews and provide exclusive information about herself for 30,000 yuan, about $4,300.
Although police have been attempting to remove the video from the Internet, it is still available online.
A man from Hubei province is suspected of spreading the video and police are investigating, the bureau said.