General T’ang Tsai-li passed in 1898 the competitive examinations conducted by the Shanghai School of Languages and was sent to Japan as a government student. He was among the first group of Chinese students sent to the Japanese Military Cadet School. He entered this school in October 1901 taking a course in applied artillery and engineering and graduated from there in 1904.
In 1904 General T’ang returned to China and served under Yuan Shih-kai who was then Viceroy of Peiyang, as his staff officer, chief assistant instructor and in various other capacities at the Training Bureau. He acted as umpire at the manoeuvres held in Hokienfu, Chihli and Changtehfu Honan.
In 1900 Mr. Tang was appointed commander of the artillery regiment of the Fifth Division stationed in Shantung (Shandong). In 1908 he became chief of the department of the Training Bureau of the Metropolitan Forces. In the same year he was commissioned Lieutenant-Colonel of the artillery, chief staff officer of the manoeuvres at Chochow, Chihli and inspected the National Manoeuvre of Japan.
In 1910 General T'ang went to Urga, Mongolia as the chief of the military staff there. In the following year he returned to Peking to become the staff officer of Yuan Shih-k’ai. Upon the establishment of the Republic Yuan Shih-kai sent him as one of the Northern Delegates to negotiate with the Nanking government to effect the unification of the North and the South. He served later in the year 1912 as Military Counselor to President Yuan, being promoted as a Brigadier-General and awarded the Fourth Order of Merit.
In 1914 he became Deputy Chief of the Military Council in the President's Office and a year later he was promoted to be Chief of the Council. In February 1915 he was commissioned to act as Deputy-Chief of the General Staff. In June 1915 he was appointed Acting Deputy Chief of the General Staff which position was substantiated to him in August 1915.
In December 1915 General T'ang was ordered to act as Chief of the General Staff. In July 1916 he resigned from these posts to accept a military councillorship in the president's office.
In 1918 General T'ang was sent to Europe as the Chinese representative at the Allied Military Council. During the first part of 1919 he was at Paris as Chief Military Delegate on the Chinese Delegation to the Peace Conference. In December 1919 he was appointed Deputy Chief of the Genleral Staff although he was still in Europe making an extensive travel throughout the Balkans as well as Central and Southern Europe. While in England he was knighted (K. B. E.) by King George.
General T'ang returned to China in the summer of 1920 and resigned from the General Staff in August that year. In recognition of his services he was made a Chiangchun, of the College of Marshals with “Yen-Wei” as special title and also decorated with the Second Class Paokuang Chiaho and the Second Class Wenfu Decorations. In January 1922 he was appointed a Member of the Commission on Mongolian Affairs.
General T’ang was the wearer of the French Legion d’Honneur, Commander; the Belgian Order of Crown, Commander and the Greek Order of the Second Class.