In this study, we investigated the effects of repetition trials and working memory (WM) capacity on performance when Chinese advanced Japanese learners repeated Japanese sentences. We found that four repetition trials were sufficient to improve the rate of morpheme reproduction, and three repetition trials were sufficient to improve the rate of idea unit reproduction. Learners are more likely to deepen their understanding of the sentence as the number of trials increases. Multiple repetitions also promote the connection between the meaning and the form. We also clarified that successful repetition exercises required participants with high WM capacity to repeat the sentence up to two times and for those with low WM capacity up to three or four times. Additionally, we found that there was no difference in reaction time, and there was a tendency for learners to produce utterances immediately after listening. Furthermore, in terms of fluency, four times were sufficient to improve the oral fluency, but regardless of trials, the high WM capacity group performed better than the low WM capacity group. Even if both groups were completely comprehensible, the chunks used at the time of oral reproduction may be different. We recommend that efficient learning requires learners of Japanese to repeat the same sentence and control the number of exercises according to WM capacity.