After a review of translation textbooks published in the period 2013-2018, it is found that translation standards in most books are elaborated from the perspective of sentence instead of discourse. Despite its partial consistence with the sentence translation standard, the discourse translation standard focuses more on the independence of the target text. It is vital to uphold such translation mentality in professional translation contexts. This paper extends the theories of “a Second Original in Its Own Right”, “Idiomaticalness” and “Target Text Norm Observation” into the theory of independence of the target text, covering independent norms, natural expression, and coherent discourse.