For learning English as a foreign language, the efficiency of the approach of incidental vocabulary acquisition depends on the word frequency and text coverage. However, the statistics of English corpus reveals that English is a language that has a large vocabulary size but a low word frequency as well as text coverage, which is obviously not in favor of the approach. Also, the statistics reveals that, by learning English words from reading incidentally as the approach claims, the learners will have to add up their reading out of class to a large quantity as ten times as that in class. Accordingly, it will be too much for them to do and clearly it is unfeasible to these non-English major learners, who could not probably have time to spend in reading so much just for picking up new words incidentally. This paper aims to prove that the approach is not feasible at all to EFL learning in China.