Nyorai kuenderera mberi kweiyi ndima - Kumitambo yeOlympic ya2016, Sun akakunda mumakwikwi emamita mazana maviri akasununguka aine nguva ya1:44.65, achipedza masekondi 0.55 pamberi pemumhanyi wechipiri Chad le Clos. Yaiva zita rokutanga guru renyika yose raSun mumutambo uyu, uye akava mutambi wokutanga weChinese kuti akunde menduru yegoridhe mumutambo uyu. Akakunda menduru yesirivha mumamita mazana mana akasununguka aine nguva ye3: 41.68, achipedza 0.13 masekondi kumashure kwaMack Horton weAustralia. Sun akapedza ari wechi16 mumakwikwi e1 500 metres freestyle
, achicherekedza pa 15:01.97. Nemenduru yake yegoridhe yemamita mazana maviri yemahara uye menduru yake yegoridhe yemamita mazana mana nemakumi mashanu emamita kubva kuma2012 Summer Olimpiki, Zuva rakava wekutanga kushambira munhoroondo kuhwina menduru yegoridhe yeOlympic mumitambo yemamita mazana maviri, mazana mana, uye mazana mashanu emamita.