The history of the People's Republic of China details the history of mainland China since October 1, 1949, when, after a near complete victory by the Chinese Communist Party (CCP) in the Chinese Civil War, Mao Zedong proclaimed the People's Republic of China (PRC) from atop Tiananmen. The PRC has for several decades been synonymous with China, but it is only the most recent political entity to govern mainland China, preceded by the Republic of China (ROC) and thousands of years of imperial dynasties.

Based on this passage, who established the peoples republic of china in 1949? Let's give stream of consciousness first:
To answer the question, consider the following: The history of the People's Republic of China details the history of mainland China since October 1, 1949, when, after a near complete victory by the Chinese Communist Party (CCP) in the Chinese Civil War, Mao Zedong proclaimed the People's Republic of China (PRC) from atop Tiananmen.
So, the final answer is Mao Zedong.