Rubuta ci gaba don wannan sakin layi - Don Wasannin Olympics na 2012, Sun an dauke shi a matsayin wanda aka fi so a cikin mita 400 da mita 1500 na kyauta
, da kuma dan takara a tseren mita 200 na 'yanci. A cikin wasansa na farko, tseren mita 400, ya lashe lambar zinare tare da lokacin 3:40.14, ya karya rikodin wasannin Olympic da Ian Thorpe ya yi a baya kuma ya zama dan wasan maza na farko na kasar Sin da ya lashe lambar zinare a gasar Olympics. Lokacinsa kuma shine na uku mafi sauri a tarihi, 0.07 seconds daga rikodin duniya, kuma ya kafa sabon rikodin Asiya. Bayan kwana guda na murmurewa, Sun ya yi gasa a tseren mita 200 na 'yanci. Ya lashe lambar azurfa a wasan karshe, tare da Park Tae-hwan tare da lokacin 1: 44.93, sabon rikodin ƙasa. Kashegari, Sun ya yi iyo a kafa ta anga a tseren tseren mita 4 × 200 don taimakawa tawagar kasar Sin ta lashe tagulla, lambar yabo ta farko ta kasar Sin a gasar tseren maza.