The purpose of this study is to analyze the effects of journal writing using mathematics picture books on children’s
mathematical ability and language expression. A total of 50 five year old children(25 children in experimental group
and 25 children in comparative group) enrolled in two kindergartens participated in this study. The experiment was conducted
once a week for twelve weeks. The experimental group participated in journal writing using mathematics picture books. Its
process was as follows: reading mathematical picture books, sharing ideas, writing journal, and sharing journals. In the comparative
group, reading mathematics picture books was conducted but journal writing was not. The ANCOVA was used to
analyze the data. The results of this study is summarized as follows. First, the effects of journal writing using mathematics picture
books on children’s mathematical ability was statistically meaningful. There were meaningful differences on children’s
mathematical ability such as algebra, number and operation, geometry, and measurement. Second, the effects of journal writing
using mathematics picture books on children’s language expression was statistically meaningful. There were meaningful
differences on children’s language expression such as correspondence of contents and number of words. In conclusion, it is
revealed that journal writing using mathematics picture books positively affects children’s mathematical ability and language
expression.