In this paper, taking the Chinese Grade 1, Grade 2 and Grade 3 students who learn the Japanese language as the object of the survey, a questionnaire was made about "Exploring the acquisition situation and acquisition process of the Marked and Unmarked Potential Expressions of Unpaired Verbs". Several conclusions can be got from this investigation:
1. For the Grade 1, Grade 2 and Grade 3 students, it is easy for acquiring the marked potential expressions; however, it is difficult for the situation of the unmarked potential expressions.
2. For the acquisition of the marked potential expressions, it is not so difficult for the Grade 1 students, and it becomes easy from the Grade 2.
3. For the acquisition of the unmarked potential expressions, although there is some improvement with the growth of the school year, it is still difficult for all the students.
According to the investigation results, the factors that influences the easy and difficulty of the acquisition were studied. The results show that "All language transfer and textbooks and overgeneralization can become the factors that help and hinder the acquisition".