Process writing represents a shift of emphasis in teaching writing from the product of writing activities to the process in which the written text can be developed. Unfortunately, many people only recognize the explicit part in the process writing which consists of activities, such as prewriting, drafting, revising, rewriting, but neglect its implicit part in which the meaning in the writer's mind develops from the writer-based text to the reader-based text. This paper is to expatiate on this implicit process, especially in academic English writing, with the hope of offering useful ideas to our learners for their writing activities.