In April 1949, representatives from both sides met in Beijing and attempted to negotiate a ceasefire. While the negotiations were ongoing, the Communists were actively making military maneuvers, moving Second, Third and Fourth Field Army to the north of the Yangtze in preparation for the campaign, pressuring the Nationalist government to make more concessions. The Nationalist defenses along the Yangtze were led by Tang Enbo and 450,000 men, responsible for Jiangsu, Zhejiang and Jiangxi, while Bai Chongxi was in charge of 250,000 men, defending the portion of the Yangtze stretching from Hukou to Yichang.

The Communist delegation eventually delivered an ultimatum to the Nationalist government. After the Nationalist delegation was instructed to reject the ceasefire agreement on 20 April, the PLA began gradually crossing the Yangtze River on the same night, launching a full assault against Nationalist positions across from the river.

Between 20 April and 21 April, 300,000 men from the PLA crossed from the north to the south banks of the Yangtze River. Both the Second Fleet of the Republic of China Navy and the Nationalist fortress in Jiangyin soon switched sides to the Communists, allowing the PLA to penetrate through Nationalist defenses along the Yangtze. As the PLA began landing on the south side of the Yangtze on 22 April and securing the beachheads, the Nationalist defense lines began to rapidly disintegrate. As Nanjing was now directly threatened, Chiang ordered a scorched earth policy as the Nationalist forces retreated toward Hangzhou and Shanghai. The PLA stormed across the Jiangsu province, capturing Danyang, Changzhou and Wuxi in the process. As the Nationalist forces continued to retreat, the PLA was able to capture Nanjing by 23 April without encountering much resistance.

On 27 April, the PLA captured Suzhou, threatening Shanghai. In the meanwhile, the Communist forces in the west began attacking Nationalist positions in Nanchang and Wuhan. By the end of May, Nanchang, Wuchang, Hanyang were all under the control of the Communists. The PLA continued to advance across the Zhejiang province, and launched the Shanghai Campaign on 12 May. The city center of Shanghai fell to the Communists on 27 May, and the rest of the Zhejiang fell on 2 June, marking the end of the Yangtze River Crossing Campaign.