| Challenger Shenzhen 2 | 10/27 07:35 | 45 | [108] Н. Срирам Баладжи v Файинг Сун [226] | 3-6,4-6 | |
| Challenger Liuzhou | 10/23 05:05 | 25 | [216] Зе Чжан v Файинг Сун [226] | 6-4,6-3 | |
| Challenger Ningbo | 10/16 08:40 | 25 | [236] Файинг Сун v Раду Албот [98] | 4-6,3-6 | |
| Challenger Ningbo | 10/15 02:30 | 54 | Майкл Чжу v Файинг Сун | 3-6,4-6 | |
| Challenger Ningbo | 10/14 04:15 | 46 | Файинг Сун v Hossam, Youssef | 4-6,7-5,7-5 | |
| Challenger Ningbo | 10/13 03:00 | 45 | Файинг Сун v Ли, Юанфенг | 6-3,6-2 | |
| ATP Shenzhen | 09/22 08:10 | 64 | [342] Маусли, Брэдли v Файинг Сун [239] | 7-6,6-3 | |
| ATP Shenzhen | 09/22 07:20 | 64 | Смычек, Тим v Файинг Сун | Cancelled | |
| Челленджер Шанхай | 09/08 06:45 | 45 | Файинг Сун v Винаяк Шарма Каца | 6-7,3-6 | |
| Челленджер Чжанцзяган | 09/04 02:00 | 54 | [316] Фредерико Феррейра Сильва v Файинг Сун [273] | 7-6,6-1 | |
| Челленджер Чжанцзяган | 09/03 03:15 | 46 | Файинг Сун v Маниш Сурешкумар | 6-3,6-3 | |
| Челленджер Чжанцзяган | 09/02 03:10 | 45 | [273] Файинг Сун v Мукунд, Саши Кумар [384] | 6-1,6-2 | |
| Challenger Gwangju Qual | 08/11 01:30 | 45 | Файинг Сун v Дзюмпэи Ямасаки | 1-6,6-2,2-6 | |
| Цзинань, Китай | 08/05 02:00 | 46 | Так Кхунн Ванг v Файинг Сун | 7-6,6-7,6-2 | |
| Цзинань, Китай | 08/04 07:30 | 45 | [190] Ти Чжен v Файинг Сун [313] | Retired | |
| ITF China F10 | 07/10 06:10 | 25 | Файинг Сун v Li, Jianhui | 2-6,6-7 | |
| ITF China F8 | 06/08 02:50 | 27 | [298] Файинг Сун v Чже Ли [322] | 6-2,3-6,2-6 | |
| ITF China F8 | 06/07 02:00 | 26 | Файинг Сун v Вильям Ма | 6-1,6-1 | |
| ITF China F8 | 06/04 02:00 | 25 | Файинг Сун v Чен, Лиран | 6-4,6-3 | |
| ITF China F7 | 05/30 02:30 | 26 | [298] Файинг Сун v Чже Ли [322] | 5-7,4-6 | |
| ITF China F7 | 05/29 03:30 | 25 | Ву, Хао v Файинг Сун | 6-2,2-6,2-6 | |
| ITF China F6 | 05/20 02:30 | 29 | [475] Патрик Никлас-Салминен v Файинг Сун [309] | 2-6,6-4,6-4 | |
| ITF China F6 | 05/19 03:00 | 28 | Кенто Такеучи v Файинг Сун | 1-6,3-6 | |
| ITF China F6 | 05/18 02:00 | 27 | Файинг Сун v Ригеле Te | Retired | |
| ITF China F6 | 05/17 02:00 | 26 | [221] Синь Гао v Файинг Сун [309] | 3-6,3-6 | |
| ITF China F6 | 05/15 02:00 | 25 | Файинг Сун v Цунг-Хао Хуан | 6-1,6-2 | |
| ITF China F5 | 05/09 02:00 | 25 | Файинг Сун v Рейнвейн, Сами | 2-6,3-6 | |
| ITF China F4 | 05/04 03:00 | 27 | Файинг Сун v Ригеле Te | 6-7,2-6 | |
| ITF China F4 | 05/02 03:00 | 26 | Файинг Сун v Ся, Чжихао | 2-6,6-3,6-3 | |
| ITF China F4 | 04/30 05:20 | 25 | Файинг Сун v Ся, Хайтун | 6-2,6-3 |
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.