That is an original song, composed by Chen Guangrong and performed by the Ai Xuan Orchestra. Search for the missing killer whistle on Baidu or Ringtone Home, and you can see the link. Download the computer desktop, use pp assistant to add the song, make the song, set the beginning and end, click save and import, it will be your mobile phone ringtone, free and no need to jailbreak, the process is simple