| Type: | Bishop |
| Honorific-Prefix: | Most Reverend |
| Melchior Sun De-zhen | |
| Vicar Apostolic of Anguo | |
| Church: | Catholic Church |
| Term: | 1929–1936 |
| Predecessor: | None |
| Successor: | John Baptist Wang Tseng-yi |
| Ordination: | 24 Jan 1897 |
| Consecration: | 28 Oct 1926 |
| Consecrated By: | Pope Pius XI |
| Birth Date: | 19 Nov 1869 |
| Birth Place: | Beijing, China |
| Death Date: | 23 Aug 1951 (age 81) |
Melchior Sun Dezhen, C.M. or Melchior Sun Souen (Chinese: 孫德禎) (1869–1951) was a Roman Catholic prelate who served as Vicar Apostolic of Anguo (1929–1936), Titular Bishop of Esbus (1926–1929), and Prefect of Lihsien (1924–1926).
Melchior Sun Dezhen was born in Beijing, China on 19 Nov 1869 and ordained a priest in the Congregation of the Mission on 24 Jan 1897.[1] [2] On 15 Apr 1924, he was appointed during the papacy of Pope Pius XI as the first Prefect of Lihsien and installed on 17 Jul 1924.On 24 Jun 1926, he was appointed during the papacy of Pope Pius XI as Titular Bishop of Esbus and on 28 Oct 1926, he was consecrated bishop by Pope Pius XI, with Carlo Cremonesi, Titular Archbishop of Nicomedia, and Celso Benigno Luigi Costantini, Titular Archbishop of Theodosiopolis in Arcadia, serving as co-consecrators.On 15 Jul 1929, he was elevated during the papacy of Pope Pius XI as Vicar Apostolic of Anguo after the Prefecture was promoted to an Apostolic Vicariate.He served as Vicar Apostolic of Anguo until his resignation on 7 Feb 1936.He died on 23 Aug 1951.
While bishop, he was the principal consecrator of:
and the principal co-consecrator of: