Two experiments were carried out to investigate the associative relationship between lexical and conceptual representations in Chinese proficient learners of Japanese language by using the picture-word Stroop naming task. In experiment 1, the subjects were required to name pictures in the second language while ignoring printed Kanji (Japanese ideogram) words. In experiment 2, other subjects were asked to name pictures in the native language while ignoring printed Kanji words. The results of two experiments suggested the following three points. The first is that when naming pictures, semantic processing of Japanese Kanji words is also performed at the same time. The second point is that in the mental lexicon of proficient learners, lexical and conceptual representations of Chinese-Japanese cognates and homographs were linked in the same formation degree. The third is that when the input language and output language were different in the picture naming task, Stroop interference could arise at both the semantic processing stage and the production stage.