What is the name of a traditional Chinese biography book?

Generally called "person's name (word/number/posthumous name) + biography", such as Mr. Lin Yutang's "Su Dongpo's biography" special use of "biography", such as Mr. Zhu Dongrun's "Zhang Juzheng's biography". Perhaps what you want to say is that biographies are often compilations of biographies of several people, which are naturally shorter in length. This is the case with Chen Shou's Three Kingdoms, for example, of the Western Jin Dynasty. Others also have personal biographies, such as "Mr. Willow biography", there are juniors for the predecessor of the biography, the disciple for Mr. biography, friends with each other biographies and so on, these are more sporadic and trivial. I hope my answer to your satisfaction.