【Abstract】This paper discusses the previous and current research including different hypotheses or models towards incidental vocabulary acquisition and English reading， revealing some factors affecting incidental vocabulary acquisition in English reading process for native Chinese learners， and finally clarifies some strategies on incidental vocabulary acquisition through English reading.
　　【Key words】second language acquisition； incidental vocabulary acquisition； English reading process
　　Introduction
　　In the past decades， a great deal of research has claimed that vocabulary is a key aspect for second language learners to acquire their language skills， including reading， writing， listening， and speaking. According to Nation （2003）， there were two kinds of vocabulary learning： direct and indirect lexical learning. In direct vocabulary learning， learners focus their attention on vocabulary knowledge when they do lexical exercises by applying memorizing techniques， whereas indirect vocabulary learning refers to the acquiring L2 lexical knowledge while learners’ goal is to draw attention to some other features other than lexical learning. Indirect vocabulary learning is also can be called “intentional” lexical learning. Hatch and Brown （2001） defined intentional learning as “being designed， planned for， or intended for a teacher or student” and incidental learning as “the type of learning that is a by-product of doing or learning something else” （p.368）. Unlike intentional vocabulary learning， incidental vocabulary acquisition （IVA） is not based on the instructional focus in the classroom pedagogical setting， as Gass （1999） considered， but takes place “as a by-product of other cognitive exercises （e.g. reading/listening） involving comprehension” （p. 319）. Therefore， incidental vocabulary acquisition requires an understanding of the surrounding context of the unknown words， and the proper amount of attention the learner spends on both correct meaning and form of those words.
　　In this paper， the current literature theoretical models are reviewed on incidental vocabulary acquisition for the readers/learners during the L2 reading process. Next， some factors affecting incidental vocabulary acquisition in the L2 reading process are discussed. After illustrating the pedagogical implications， I finally provide a conclusion on the main concerns of this paper.
　　Theoretical Models in the Study of IVA
　　Currently， in many empirical studies， “Depth of Processing Model” and “Involvement Load Hypothesis” are frequently applied to testify the process and effect of incidental vocabulary acquisition from the aspects of cognitive psychology.