The student, Wang Dong, said on China's Twitter-like Weibo, "Only f**king idiots stay patriotic after entering college" and "I won't be patriotic my whole life" on Wednesday.
A university investigation revealed that the Weibo user was one of their students.
The university said Wang had used insults and ridiculed his patriotic roommates since school started on September 9.
The decision signed by the university's Party Committee Publicity Department was based on the university's regulations of student status management.
"The school decided within the framework of school rules and regulations," Wang Sixin, a professor at the Communication University of China in Beijing, told the Global Times on Monday.
The internet is not free from regulation. The country's Internet Security Law states that insults against China should not be posted on Weibo, Wang said.
Screenshots which went viral show Wang saying on Weibo that he was jingri, or "spiritually Japanese," otherwise he would not learn Japanese language.
He said, "I may be forced to commit crimes by your country."
"Your country" is a sarcastic reference to China used by people who declare to be spiritually of other nationalities.
Although some thought expulsion was too harsh since Wang enjoys freedom of speech online, comments liked most under news posts usually agree with the school's decision.
"The Chinese have a strong devotion to the nation and netizens severely criticize insults," Wang said, "and never consider them funny."
This story was originally published in Global Times.
