Abstract: The paper aims to make a comparison study between word association of native speakers and that of Chinese English learners (CELs). Through data analysis of the word association results, the nature of the second language (L2) mental lexicon is explored. A continuous free word association test (WAT) was conducted to 150 students from Dalian University of Technology (DUT). And the Minnesota word association norms are selected as a native speakers' word association test for the comparison. The results of WATs are classified and analyzed with respect to response type and part of speech. The major findings in the paper are as follows: (1) The words in L2 mental lexicon are essentially semantically-related, just like the mental lexicon of L1 speakers. But phonological relation plays a more important role in L2 mental lexicon than in L1 mental lexicon. (2) Nouns are easy to be activated for both native speakers and L2 learners. And responses of the same part of speech as the stimulus word are easier to be activated. (3) Difference in culture and limitation of language competence may cause the different word association of natives and L2 learners. And L2 learners' native language is likely to have influence on their L2 mental lexicon. Keywords: mental lexicon; word association; Chinese English learners Resume: Le document vise a faire une etude comparative entre l'association de mots entre les locuteurs de langue maternelle anglaise et les apprenants chinois de l'anglais (ACA). Grâce a l'analyse des donnees des resultats d'association de mots, la nature de lexique mental de la deuxieme langue (L2) est exploree. Un test continu de l'association de mots libre (TAM) a ete realisee chez 150 etudiants de l'Universite de Technologie de Dalian (UTD). Et les normes d'association de mots de Minnesota sont selectionnee comme un test d'association de mots chez les locuteurs natifs pour faire la comparaison. Les resultats de TAM sont classes et analyses en fonction du type de reponse et de la partie du discours. Les conclusions principales de cet article sont les suivantes: (1) Les mots dans le lexique mental L2 sont semantiquement lies, tout comme le lexique mental des locuteurs de L1. Mais les relations phonologiques jouent un role plus important dans le lexique mental L2 que dans le lexique mental L1. (2) Les noms sont faciles a etre actives pour les locuteurs natifs et les apprenants de L2. Et les reponses de la meme partie du discours en tant que le mot de stimulus sont plus faciles a activer. (3) La difference de culture et la limitation de la competence linguistique peuvent causer une association de mots differente des autochtones et des apprenants de L2. Et la langue maternelle des apprenants de L2 est susceptible d'avoir une influence sur leur lexique mental L2. Mots-cles: lexique mental; association de mots; apprenants chinois de l'anglais INTRODUCTION For any language, vocabulary plays a significant role. Without vocabulary, communication cannot happen in a meaningful way. Thus lexical researches have aroused more and more interest among linguists. And the study of mental lexicon has drawn special attention from researchers. In the past thirty years, there has been great development in lexical research. Researchers make great efforts to try revealing the organization of mental lexicon which contains an extremely large amount of information. By now, agreement has been reached on the organization of the fust language (Ll) mental lexicon. Researchers commonly agree that words in L1 mental lexicon are connected with each other semantically and are stored in mind around a semantic network. However, there is still disagreement among researchers on the organization of the second language (L2) mental lexicon. Three kinds of viewpoints have been advanced, namely phonological view, semantic view and syntactic view. With the application of word association test (WAT) to linguistic study, more and more researchers have started to use this efficient method in the study of L2 mental lexicon to try to find answers to this unsettled issue. …