1949年前国民党腐败，土共土改和不遗余力的抗日得到民心。
土共得到民众的支持有着高超的军事技巧和士气 赢得中国政权

原文： https://history.state.gov/milestones/1945-1952/chinese-rev

During World War II, popular support for the Communists increased. U.S. officials
                    in China reported a dictatorial suppression of dissent in Nationalist-controlled
                    areas. These undemocratic polices combined with wartime corruption made the
                    Republic of China Government vulnerable to the Communist threat. The CCP, for
                    its part, experienced success in its early efforts at land reform and was lauded
                    by peasants for its unflagging efforts to fight against the Japanese
                    invaders.

As the civil war gained strength from 1947 to 1949, eventual Communist victory
                    seemed more and more likely. Although the Communists did not hold any major
                    cities after World War II, they had strong grassroots support, superior military
                    organization and morale, and large stocks of weapons seized from Japanese
                    supplies in Manchuria. Years of corruption and mismanagement had eroded popular
                    support for the Nationalist Government. Early in 1947, the ROC Government was
                    already looking to the island province of Taiwan, off the coast of Fujian
                    Province, as a potential point of retreat. Although officials in the Truman
                    Administration were not convinced of the strategic importance to the United
                    States of maintaining relations with Nationalist China, no one in the U.S.
                    Government wanted to be charged with facilitating the “loss” of China to
                    communism. Military and financial aid to the floundering Nationalists continued,
                    though not at the level that Chiang Kai-shek would have liked. In October of
                    1949, after a string of military victories, Mao Zedong proclaimed the
                    establishment of the PRC; Chiang and his forces fled to Taiwan to regroup and
                    plan for their efforts to retake the mainland