Ranked No. 4 in the Polo Golf Rankings, Xiong started the season with a win at the Thunderbird International Junior, his first victory since winning three times in 2014. He earned a second-place finish at Rolex Tournament of Champions in 2015, along with being named second-team Rolex Junior All-American. He advanced to the semifinals at the Polo Golf Junior Classic in 2015, falling to eventual champion Ryan Gerard. The Temescal Canyon senior is verbally committed to the University of Oregon.
| Rank | Event | R1 | R2 | R3 | R4 | Total |
| T24 | 2016 Rolex Tournament of Champions | 67 | 72 | 72 | 83 | 294 |
| 1 | 2016 Thunderbird International Junior | 68 | 70 | 69 | 207 | |
| T9 | 2016 Junior Invitational at Sage Valley Golf Club | 68 | 72 | 79 | 219 | |
| T57 | 2016 CB&I / Simplify Boys Championship at Carlton Woods | 78 | 82 | 73 | 233 | |
| T3 | 2015 Polo Golf Junior Classic | 73 | 74 | 147 | ||
| T10 | 2015 The PING Invitational | 80 | 74 | 76 | 230 | |
| T26 | 2015 The Junior PLAYERS Championship presented by TaylorMade-adidas Golf | 78 | 69 | 75 | 222 | |
| 3 | 2015 IMG Academy Junior World Championship | 71 | 69 | 75 | 73 | 288 |