No official reason has been given, but the bear has frequently been compared to the country's president, Xi Jinping.
Images of the bear were also deleted from Weibo and Wechat, a popular Chinese messaging app. Articles about the censorship circulated on Wechat, mentioning rumours that Winnie-the-Pooh programmes were also set to be banned.
Memes comparing Xi Jinping to Winnie are believed to have first emerged in 2013.
Winnie The Pooh has reportedly been blacklisted on social media by the Chinese Government.
The National Congress event is being held in autumn and will see elections for the most senior positions in China's ruling Communist Party and Politburo, its main policy-making committee.
"Historically, two things have been not allowed: political organizing and political action".More news: 2 sisters killed in crash into in home mourned at vigil
"I think the Winnie issue is part of this trend", he added.
Currently, attempts to write "Winnie the Pooh" in China's famous social network Weibo end up with a pop-up warning "illegal content".
Over the weekend, posts that carried images and texts related to the fictional bear were removed by Chinese censors from sites including WeChat and Weibo because it has "become too politically sensitive", the Financial Times reported. A similar comparison was made with Xi as Pooh and Japan's prime minister Shinzo Abe as Eeyore, the sad donkey.
And what was described as the "most censored image of 2015" by political consultancy Global Risk Insights showed another comparison, this time featuring Winnie in a toy auto.
Correction: This story has been edited to reflect the fact that some images of Winne the Pooh are still searchable on Chinese social media.