Abstract: Semantic interference effect（SIE）in the picture-word interference paradigm is commonly interpreted as support of the assumption of lexical selection by competition. Two contrasting polarities of semantic contextual effect are observed in picture-word interference paradigm: semantic interference or semantic facilitation. Many factors attribute to these two results and the assumption of lexical selection by competition and comparative level of categorization are the main two theories. The model of selection by competition assumes that the concepts represented by semantic-related distractors and target picture will interactivate and lead to semantic interference ,and lexical nodes compete for selection; The assumption of comparative level of categorization assume that the crucial factor in determining semantic effect and its magnitude is the comparative levels of categorization between distractors and the target pictures .If they are from the same level of the same category , SIE will arise; If they are from the different level of the same category, semantic facilitation will arise. This paper gives a revision of present studies and points out the research direction in the future

Key words: picture-word interference paradigm, semantic effect, semantic interference, semantic facilitation