The May 30th Movement
Following the establishment of the first KMT-CPC cooperation, the CPC continued to lead the workers' movement nationwide. On May 1, 1925, the All-China Federation of Trade Unions was founded in Guangzhou, and CPC members Lin Weimin (1887-1927) and Liu Shaoqi (1898-1969) were elected president and vice president.
On May 15, the Japanese owner of a cotton mill in Shanghai shot dead Gu Zhenghong (1905-1925), a CPC member and workers leader, and wounded a dozen others. The CPC Central Committee decided to mobilize the local people to stage an anti-imperialist demonstration in the International Settlement. On May 30, as the workers and students protested in the street in support of the textile workers, the British police suddenly opened fire on the Nanjing Road, killing 13 and wounding many others. This was known as the May 30th Massacre. In the days after, there were incidents of British and Japanese police killing Chinese civilians in Shanghai and other cities.
The massacres enraged the whole nation. The CPC Central Committee decided to set up an action committee composed of Qu Qiubai, Cai Hesen, Li Lisan, Liu Shaoqi and Liu Hua (1899-1925) to organize demonstrations and strikes by workers, students and shopkeepers in Shanghai. Under the CPC's leadership, the May 30th Movement swept the whole country, and about 17 million people from all walks of life participated, forming a tremendous anti-imperialist movement with an international impact.
The CPC's influence was reinforced during the May 30th Movement, and its membership increased tenfold within a year. The movement directly led to the general strikes in Guangzhou and Hong Kong, which lasted for 16 months with 250,000 participants and sparked a further upsurge of revolution across China.
五卅運動
第一次國共合作建立后，中國共產黨繼續領導全國的工人和群眾運動。1925年5月1日，中華全國總工會在廣州正式成立，共產黨員林偉民、劉少奇分別當選為正、副委員長。5月15日，上海內外棉七廠的日本資本家槍殺工人代表、共產黨員顧正紅，打傷工人10余人。中共中央決定在租界內舉行大規模的反帝示威活動。5月30日，上海工人和學生舉行街頭宣傳和示威游行，租界的英國巡捕在南京路上突然開槍，打死13人，傷者不計其數，制造了震驚全國的五卅慘案。此后幾天，在上海和其他地方又連續發生英、日等國軍警槍殺中國人的事件。
這些事件，激起了全國人民的極大憤怒。中共中央決定由瞿秋白、蔡和森、李立三、劉少奇和劉華等組成行動委員會，組織全上海工人罷工、學生罷課、商人罷市的抗議運動。在中國共產黨的領導和推動下，五卅運動迅速席卷全國，約有1700萬人直接參加了運動，形成了全國規模的反帝怒潮和具有廣泛國際影響的反帝斗爭。
五卅運動擴大了中國共產黨在全國的影響，黨員數量一年內增加了10倍。這一運動直接推動了歷時16個月、25萬人參加的省港大罷工的興起，對大革命高潮的形成起到重要的推動作用。
