Before I list a few recommendations, I'd like to present two realities for anyone else ever wondering about this in the future:
People in China don't really buy books.
So many books, like music, film and television, is easily downloaded in China. Mainstream book stores exist in China (ex: the Xinhua Bookstore chains), but mostly these stock text books and books on DIY, self-help, business management, the classics, etc... They have very minimal fiction or new Chinese writers, and certainly nothing reflective of a 'reading culture.' If people at all are buying books, they are buying them online (Taobao, Yihaodian, Tmall, etc...) Even Amazon has a site in China now!
People in China don't really buy used things.
Purchasing things is related to quality, which in China is deeply connected to how you are seen by other people, and so the idea of buying something used (or of low/lesser quality) usually seems absurd to most upper-middle class.
With that said, here are some recommendations, but I can't verify that they are still open:
- Zhengyang Shuju (正阳书局), 76 Langfang Ertiao, (Off Qianmen Dajie), Chongwen district, Phone: 6303 9616
(正阳书局 is probably your best shot)
Beijing International Book City (北京出版发行物流中心), 13 Taihu Zhengfu Dajie, Hechuanye Park, Tongzhou district, Phone: 8080 8888
Page One, 3B201, China World Trade Centre Phase 3, 1 Jianguomenwai Dajie, Chaoyang district, Phone: 8535 1055