Mathematical disposition could influence learning and performance, they usually determine how well students motivate themselves and persevere in the face of difficulties, and they influence the choices-making about coursework, and even educational and career paths. The aim of this study is to investigate the same students' mathematical disposition types and changes from 6th grade to 8th grade, and examine the relationship between mathematical disposition and mathematics achievement. The results showed that students' math disposition can be classified into three kinds of leaning orientation: give-up, peer-cooperative for mastery, and self-regulated for mastery. The students possessing the orientation of self-regulated for mastery perform best, followed by peer-cooperative for mastery, and give-up students perform weakest. The variance explained by the types of mathematical disposition in 6th grade is about 7%. While the students promoted to 8th grade, these three types of students still have the same pattern in mathematics achievement, the variance explained is about 5%. To examine the changes of mathematical disposition from 6th to 8th grade, there were three kinds of disposition change pattern: High and stable, moderate and stable, and decline. Only about 7.4% of students are the decline, most students' mathematical dispositions are quite stable across 3 years, especially the self-regulated for mastery and the peer-cooperative for mastery. This study proved the relationship between the students' mathematical disposition and achievement. This suggests that mathematics educators need to focus not just on the development of math knowledge and skills, but on the development of the mathematics disposition.