Hello, the soundtrack you are talking about should be "Memories".

Also attached are all the music from those years:

01. Blue dots on the uniform (soundtrack)

02. Never look back - Ke Zhendong/Chen Yanxi/ Hao Shaowen/Cai Changxian/Yan Shengyu/Wanwan

03. Masturbation (soundtrack)

04. Love syndrome - Huang Shujun

05. Girl's ponytail (soundtrack)

06. The Last Wave (Music)

07. Each Wing (Music)

08. Childish - Michelle Chen

09 .Fighting match dedicated to you (soundtrack)

10. Idiot (soundtrack)

11. Lonely caffeine - Ke Zhendong

12. Without you Youth (Music)

13. Meeting You in the Crowd - Lin Yuqun

14. Those Years - Hu Xia

15. Memories (Music)