The study of stereometry is an important component for the development of mathematical competence of students of students of vocational school of machine building profile. However, students usually neglect studying this subject, find it boring and unnecessary. The lack of interest of students leads to a low level of development of mathematical competence, which subsequently leads to an unskilled middle-level employee. The article shows the expediency of using project training for the development of mathematical competence of students of vocational school of machine building profile. The author analyzed the concept of "project", considered the classification of educational projects and stages of implementation of the educational project. Experience shows that the classification of the stages of organization, development, planning of a training project does not affect the distribution of functions of the main participants of the project - the teacher and students. The role of the organizer and the coach of the project is assigned to the teacher. The student's activity in the learning project is to execute and present the results. The results of the pedagogical experiment, which was aimed at the development of mathematical competence of students of vocational school of machine building profile through project training in studying the course of stereometry, are presented. It is determined that the introduction of project training in the process of learning stereometry provides positive trends in the formation of mathematical competence due to a more complete implementation of the connection of theory with practice, the creation of their own product and the ability to demonstrate it.