It seems that it is critical to comprehend mathematics as a tool subject in order to understand a number of calculations in the professional subjects in the vocational high schools. This study is designed to determine "how much mathematics is connected to specialized subjects in terms of mathematical content at vocational high schools". To investigate the research questions, this study examined the connections between the mathematical topics included in professional subjects and those of mathematics subjects in the vocational high school. In the end, this study suggest that is should be necessary to make new mathematics textbook which reflects the reality and needs of the present vocational high school students.