The invention belongs to the technical field of precision machining and testing, and provides a fixed angle indexing and positioning fixture used for positive N prism parts. A additional indexing device does not need, the indexing characteristics of the positive N prism and the structural characteristics of a positioning baffle are used, and he indexing and positioning of the multiplication of 360degree/N and the multiplication of 360 degree/N plus the certain angular alpha are achieved by combining with the flip motion of the baffle. The fixed angle indexing and positioning fixture used forthe positive N prism parts has the advantages of being simple in structure, high in indexing range, high in indexing accuracy, reliable in positioning, convenient to index and the like, is widely usedin the indexing and positioning operation of the machining and measurement of the positive N prism, and has a good market application prospect.