| ITF M25 Hengyang | 06/22 03:00 | 28 | Тцунг-Хао Хуанг v Файджинг Сун | 2-6,3-6 | |
| ITF M25 Hengyang | 06/21 03:15 | 27 | Garrett Johns v Файджинг Сун | 0-6,1-6 | |
| ITF M25 Hengyang | 06/20 03:00 | 26 | Лоран Рошет v Файджинг Сун | 1-6,4-6 | |
| ITF M25 Hengyang | 06/19 05:00 | 25 | Yecong Mo v Файджинг Сун | Retired | |
| ITF M25 - Лужу | 05/31 02:00 | 27 | Дзие Чуи v Файджинг Сун | Retired | |
| ITF M25 - Лужу | 05/30 05:40 | 26 | Тцунг-Хао Хуанг v Файджинг Сун | 5-7,2-6 | |
| ITF M25 - Лужу | 05/29 02:00 | 25 | Liran Chen v Файджинг Сун | 4-6,3-6 | |
| ITF M25 - Луан | 05/19 02:30 | 29 | Дзие Чуи v Файджинг Сун | 5-7,4-6 | |
| ITF M25 - Луан | 05/18 02:30 | 28 | Файджинг Сун v Yecong He | 6-2,6-2 | |
| ITF M25 - Луан | 05/17 05:40 | 27 | Хонг Кит Вонг v Файджинг Сун | 0-6,1-6 | |
| ITF M25 - Луан | 05/16 03:30 | 26 | Риота Танума v Файджинг Сун | 5-7,3-6 | |
| ITF M25 - Луан | 05/15 03:10 | 25 | Sheng Hao Zhou v Файджинг Сун | 1-6,1-6 | |
| ITF M25 Wuhan | 05/10 02:00 | 27 | [385] Ян Бай v Файджинг Сун [284] | 7-6,6-1 | |
| ITF M25 Wuhan | 05/09 02:00 | 26 | Такуто Ники v Файджинг Сун | 6-7,3-6 | |
| ITF M25 Wuhan | 05/08 02:00 | 25 | [386] Ксин Гао v Файджинг Сун [284] | 1-6,6-2,4-6 | |
| ITF M15 Wuhan | 05/04 02:00 | 28 | Файджинг Сун v Шо Шимабукуро | 7-6,4-6,3-6 | |
| ITF M15 Wuhan | 05/03 02:00 | 27 | Юки Мочизуки v Файджинг Сун | 7-6,6-7,2-6 | |
| ITF M15 Wuhan | 05/02 02:00 | 26 | Pak Long Yeung v Файджинг Сун | 2-6,4-6 | |
| ITF M15 Wuhan | 05/01 02:00 | 25 | Рей Хо v Файджинг Сун | 4-6,5-7 | |
| Challenger Nanchang | 04/22 08:00 | 24 | [286] Файджинг Сун v Ригеле Те [412] | 4-6,4-6 | |
| Challenger Anning | 04/15 08:50 | 24 | [245] Андрей Мартин v Файджинг Сун [323] | 6-3,6-1 | |
| Чалънджър - Чжанцзяган | 03/19 03:15 | 24 | [266] Юнсеонг Чунг v Файджинг Сун [329] | 6-4,6-4 | |
| Чалънджър - Чжанцзяган | 03/18 02:00 | 166 | [483] Колин Синклеър v Файджинг Сун [331] | 4-6,2-6 | |
| ITF M15 - Шарм Ел Шейх | 02/24 08:00 | 29 | Филип Бергеви v Файджинг Сун | 7-6,7-6 | |
| ITF M15 - Шарм Ел Шейх | 02/23 08:00 | 28 | Файджинг Сун v Михаел Геертс | 7-6,6-4 | |
| ITF M15 - Шарм Ел Шейх | 02/22 12:00 | 27 | Файджинг Сун v Джорджио Рика | 7-6,4-6,6-4 | |
| ITF M15 - Шарм Ел Шейх | 02/21 08:00 | 26 | Файджинг Сун v Карл Фриберг | 6-2,6-4 | |
| ITF M15 - Шарм Ел Шейх | 02/20 10:15 | 25 | Файджинг Сун v Linus Frost | 6-4,7-5 | |
| ITF M15 - Шарм Ел Шейх | 02/13 08:00 | 25 | Aaron Schmid v Файджинг Сун | 7-6,6-4 | |
| Challenger Shenzhen 2 | 10/28 04:00 | 46 | [283] Гонсало Оливейра v Файджинг Сун [226] | 7-6,7-5 |
Sun Fajing (Chinese: 孙发京; pinyin: Sūn Fājīng; Mandarin pronunciation: [swə́n fá tɕíŋ]; born 3 October 1996) is a Chinese tennis player.
Sun has a career high ATP singles ranking of world No. 351 achieved on 10 February 2020. He also has a career high ATP doubles ranking of world No. 181 achieved on 26 February 2024. He has reached 13 career singles finals posting a record of 5 wins and 8 losses, all coming on the ITF Futures tour. Additionally, he has reached 31 doubles finals posting a record of 16 wins and 15 losses, which includes 2 ATP Challenger Tour doubles titles.
Sun made his ATP main draw debut at the 2016 Chengdu Open, where he was granted a wildcard entry in the doubles draw alongside compatriot He Yecong. They were defeated in the first round by Raven Klaasen and Rajeev Ram in straight sets 4–6, 5–7.
The following year, he was again given a wildcard at the 2017 Chengdu Open with partner Te Rigele, and again he would lose in the first round to Nenad Zimonjic and Santiago Gonzalez in straight sets 4–6, 4–6.
In his third main draw appearance, he and partner Zhizhen Zhang were given a wildcard entry into the doubles draw of the 2018 ATP Shenzhen Open but lost in the first round to Marcin Matkowski and Nicholas Monroe 4–6, 2–6.
His fourth and most recent ATP appearance (also his third at the tournament) was a wildcard entry into the doubles draw of the 2019 Chengdu Open pairing up with Wang Aoran, and to round up an 0–4 record he lost to Dominic Inglot and Austin Krajicek 1–6, 6–0, [8–10].
He was given a wildcard at the 2023 China Open (tennis) partnering Zhou Yi (tennis). He received also a wildcard in doubles partnering Li Zhe (tennis) at the 2023 Rolex Shanghai Masters.