Which publishing house in China publishes the best and most authoritative books on ancient Chinese studies in China?

Which is the best is not accurate. The Commercial Press, Zhonghua Book Company, Shanghai Ancient Books Publishing House and Sanlian Bookstore are all excellent, each with its own merits. The Commercial Press pays more attention to academic works, Zhonghua Book Company is more comprehensive, Shanghai ancient books are more focused, and Sanlian Bookstore has also published a series of works such as Qian Mu. In terms of quality, I like the Commercial Press and Sanlian Bookstore.