Xinjia Peng's interest is studying the evolvement of Chinese syntax and constructions from both a diachronic perspective and a synchronic perspective – drawing on evidence from historical text and Chinese dialects. Language iconicity is another topics that intrigues her. She has conducted empirical studies researching the production and perception of iconic language in Chinese languages.

She is also interested in second language acquisition of Chinese for adult learners. Currently, she is developing a portfolio for teaching Chinese with a communicative approach.