Francesco Sambiasi (1582 in Cosenza, Calabria, Italy – January 1649 in Kanton, China), known as Bi Fangji (畢方濟) in Chinese, was a Catholic missionary to China, part of the Jesuit missions there. He was sent with the boat Nossa Senhora da Piedade to the East on 23 March 1609 and arrived in Macau in 1610. He worked in various places during his mission in China: Beijing (1613–1616), Jiading and then Shanghai (1622), a stint in Korea, then to Kaifeng (1628), Shanxi, Shandong, Nanjing (1631–1643) and then to Macau ("patente de Embaixador", 1645).

In the summer of 1645, he was appointed as the ambassador to Macau by the Southern Ming Hongguang Emperor, and was sent to petition for military aid from the Portuguese colony there.

In 1646 he worked for the Yongli Emperor as a "folk master" and the year after as a mandarin.

During his time in Nanjing, at the efforts of Xu Guangqi, Sambiasi was appointed to the Imperial Astronomical Bureau. In this role, he was made responsible for the correction of the calendar, and the observation of eclipses.

畢方濟（Francesco Sambiasi，1582年 - 1649年），耶穌會傳教士，意大利人，精于天文數學，1610年來華，先抵達澳門，1613年進入北京，後去淮安、南京、無錫、上海嘉定傳教，曾在南京城內興建護守山聖堂。南明永曆帝封他為太師。著有《畢方濟奏摺》、《靈言蠡勺》（畢方濟口授，徐光啟筆錄）、《天學略義》。