In 1881, the 17-year-old Yau Lit travelled to Shanghai, Incheon, the Three Northeast Provinces and Nanking, joined the Hongmen during the journey and aspired to revolution.

Later, he worked at the Mathematics Branch of Shatin Bureau, Guangdong, and was responsible for drawing the border between China and the then France-occupied Annam.

He introduced Yeung Kui-wan, the leader of Furen, to Sun, who had already established the Revive China Society in Honolulu, Hawaii.

He worked as the chief editor of the Thoe Lam Jit Poh (圖南日報), a pro-revolution newspaper circulating in Southeast Asia.

Following the Wuchang Uprising in 1911, Yau went to Yunnan to persuade his old friend Cai E to join the Xinhai Revolution.

Fearing Nanking would be captured, Yau Lit initiated the Chung-wo North Expedition Army (中和北伐軍) to protect the capital city.

Seeing himself at odds with Chan Siu-bak and his suggestions opposed by Hu Hanmin, Yau returned to Hong Kong to set up a school teaching Confucian values.