The world number 50 was due to play her second-round clash with Ilona Kremen on Wednesday but the match was postponed by 24 hours due to heavy rain at the WTA 125k hard-court event in Nanchang.
When the match did get underway Peng's quality told as the Chinese completed a 6-3 6-4 triumph in just 68 minutes.
Over 200 places separate the two in the world rankings and Peng broke five times to set up a last-eight tie with Wang Qiang.
Misaki Doi, seeded third, needed three sets to overcome Zhu Lin 6-2 4-6 6-3 in a match lasting over two hours.
The Japanese now faces sixth seed Zheng Saisai who was also taken the distance in her 6-7 (5-7) 6-3 6-2 success over Xu Yi-Fan.
Fourth seed Luksika Kumkhum safely saw off Marina Melnikova 6-4 6-1 to set up a quarter-final clash with wildcard Wang Yafan who beat Tereza Mrdeza 6-4 6-4.
There were also wins for Zhang Ling and Liu Fangzhou who will now meet for the right to play in the semi-finals.