China's parliament, the National People's Congress, overwhelmingly passed the constitutional changes on Sunday, the BBC reported.
The posters, written in Chinese and English, have featured phrases such as "not my president" and "I disagree".
A Twitter account @StopXiJinping has been posting links to the posters for download, and encouraging others to join what it calls "our campaign".
A user operating the account told the BBC that it was being run by Chinese university students and graduates who were living abroad but wished to remain anonymous.
The person did not give further details.
"We spoke up as we genuinely believe that Chinese citizens, overseas or at home, have the right to express opinions free from fear," the account tweeted had tweeted before the move on March 9.
The Twitter campaign has advised students to put up posters only at night, and to wear face masks.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)