| ITF M25 Гандия | 07/21 10:35 | 25 | Карлос Л-Монтагуд v Файинг Сун | Cancelled | |
| Челленджер Бендиго | 01/13 23:00 | 25 | [269] Уго Гренье v Файинг Сун [367] | 7-5,6-1 | |
| Челленджер Бендиго | 01/12 04:30 | 24 | Файинг Сун v Аарон Аддисон | 7-6,7-5 | |
| Challenger Shenzhen 2 | 10/30 02:00 | 25 | [108] Юичи Сугита v Файинг Сун [385] | 7-5,6-2 | |
| Challenger Shenzhen 2 | 10/29 02:00 | 24 | [385] Файинг Сун v Матей Сабанов [186] | 6-4,6-4 | |
| Challenger Liuzhou | 10/21 04:40 | 24 | [348] Николас Баррьентос v Файинг Сун [388] | 6-4,3-6,7-6 | |
| Challenger Ningbo | 10/15 08:10 | 25 | [101] Алехандро Давидович-Фокина v Файинг Сун [386] | 6-7,6-2,6-4 | |
| Challenger Ningbo | 10/14 05:55 | 24 | Шинтаро Имаи v Файинг Сун | 4-6,4-6 | |
| ATP Шанхай | 10/05 04:00 | 45 | [65] Марко Чеччинато v Файинг Сун [381] | 6-3,6-7,6-2 | |
| Челленджер Шанхай | 09/10 05:40 | 25 | [394] Файинг Сун v Хироки Мория [232] | 2-6,7-5,2-6 | |
| Челленджер Шанхай | 09/09 03:55 | 24 | [330] Эван Кинг v Файинг Сун [395] | 2-6,6-7 | |
| Цзинань, Китай | 09/02 07:40 | 24 | [354] Зе Чжан v Файинг Сун [395] | 6-3,6-4 | |
| Challenger Baotou | 08/27 03:40 | 25 | [395] Файинг Сун v Ян Бей [222] | 4-6,3-6 | |
| Challenger Baotou | 08/26 03:55 | 24 | Ханьи Лиу v Файинг Сун | 4-6,1-6 | |
| Челленджер Корденонс | 08/12 15:00 | 24 | [375] Джереми Ян v Файинг Сун [389] | 6-3,6-2 | |
| ITF M25 Фогау | 08/07 08:00 | 25 | [392] Файинг Сун v Ярослав Поспишил [382] | 2-6,6-7 | |
| ITF M25 Qujing | 07/14 02:30 | 29 | [281] Файинг Сун v Ян Бей [367] | 3-6,1-6 | |
| ITF M25 Qujing | 07/13 02:30 | 28 | [308] Цунь-Хуа Янг v Файинг Сун [281] | 6-7,6-7 | |
| ITF M25 Qujing | 07/12 02:00 | 27 | Файинг Сун v Джонатан Мридха | 7-6,6-1 | |
| ITF M25 Qujing | 07/11 03:25 | 26 | Файинг Сун v Казума Кавати | 6-2,6-3 | |
| ITF M25 Qujing | 07/10 05:55 | 25 | Файинг Сун v Ли Вей Тан | 6-2,6-0 | |
| ITF M25 Kunshan | 07/07 01:30 | 29 | [308] Цунь-Хуа Янг v Файинг Сун [281] | 2-6,2-6 | |
| ITF M25 Kunshan | 07/06 01:30 | 28 | Файинг Сун v Ся, Хайтун | 7-6,6-2 | |
| ITF M25 Kunshan | 07/05 01:30 | 27 | Рет Пурселл v Файинг Сун | 3-6,6-7 | |
| ITF M25 Kunshan | 07/04 01:30 | 26 | Моритани, Соичиро v Файинг Сун | 1-6,0-6 | |
| ITF M25 Kunshan | 07/02 08:05 | 25 | Чухань Ванг v Файинг Сун | 3-6,1-6 | |
| ITF M25 Иньчуань | 06/29 02:00 | 27 | [367] Ян Бей v Файинг Сун [282] | 6-4,7-5 | |
| ITF M25 Иньчуань | 06/28 06:40 | 26 | Ли Вей Тан v Файинг Сун | 0-6,4-6 | |
| ITF M25 Иньчуань | 06/28 03:20 | 25 | Yecong Мо v Файинг Сун | 4-6,3-6 | |
| ITF M25 Hengyang | 06/23 02:00 | 29 | [282] Файинг Сун v Гарри Боуршер [407] | 6-7,1-6 |
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.