Liang was one of eight players from Shanghai who had been in the city on a cultural interchange programme.
He beat Matthew Ball, of Manawatu, 4-3 in a thrilling seven set decider to win the title at the Edgar Centre on Saturday night.
On his way to the final, Liang hammered top seed Ivo Mikulec 3-0 in the quarterfinals.
Mikulec, who is from the Czech Republic but lives in Christchurch, had a tournament to forget.
A surprise 3-1 loss to junior Kelsey Amor in the pool stage turned the competition on its head, and resulted in Mikulec meeting the eventual winner in the quarterfinals.
Timea Tapai romped to the women's open title in emphatic style.
Tapai, who is from Serbia but also lives in Christchurch, was ranked 150th in the world just four years ago, and was far too good for Lucy Lu, of Auckland, in the final.
Tapai won the decider 4-0, and went on to win the women's doubles title with Sarah Her Lee and the mixed doubles title with Yi Sien Lin.
Amor and Victor Pollett won the men's doubles title.
Otago Table Tennis Association director of coaching Ben Duffy, who also competed at the weekend, said it had been a ''very good tournament''.
''It was very successful,'' he said.
''It's certainly one of the best tournaments in New Zealand, and I expect most players to return again next year.''
In total, 144 players - 32 more than a year ago - entered the open.
The group of players from China leaves Dunedin today, while selectors will start picking Otago junior and senior teams for the national championships in Christchurch in October.
The South Island individual championships will be held in Timaru next month.
