In 2004, after his success with Xiao San He Xian and signing the recording contract, he came across discussions about Han clothing on the online forum hanchc.com.
At the time, there was debate in China about the need for a traditional garment embodying the uniqueness and antiquity of Chinese culture in the same way that the kimono does in Japan and the hanbok does in Korea.
People started to use the term hanfu to distinguish the traditional clothes of Han from other ethnic groups and discuss online the history and cultural connotation of hanfu.
"It sparked my interest in the traditional stuff," Sun says. "As Han people I felt we had responsibility to restore it."
One day he saw a poem by a forum participant that impressed him and he adapted it into lyrics and composed a hanfu-themed song.
For hanfu aficionados that song, Chong Hui Han Tang ("Dating back to the Han and Tang dynasties"), a paean to their culture, became a hit.
Later he composed a series of songs related to hanfu that also struck a responsive chord with hanfu lovers.
Sun now insists on dressing in hanfu when he performs onstage, saying the attire bears the spirit and civilization of Han, and thus Chinese, people.
His wife Lyu Xiaowei has also became a tongpao, and they opened a hanfu shop called Chong Hui Han Tang in Chengdu in 2006. It is believed to have been the first physical hanfu store in China.
Playing music is now a hobby, he says, while developing hanfu is "my inescapable duty".
The couple now own 18 physical stores across China and an online store on tmall.com, and last year the value of sales of 10 hanfu stores on the online shopping platform Taobao totaled 100 million yuan ($18 million), Sun says.
"I am very happy to have seen these changes over the past 10 years. As the government highlights the need for China to bolster its confidence in its culture and traditions, now is a good time to further develop hanfu."
