In order to study the influence of the angularity of coarse aggregate on the strength of cement stabilized macadam，based on digital image processing technology，the angularity of limestone macadam and broken cobble were compared and analyzed by using equivalent elliptic method and the door orthogonal test was carried out to obtain the strength performance of combined cement stabilized macadam according to the working conditions of different angular aggregates. The test results show that unconfined compressive strength is positively related to angularity without considering the influence of cement. Under the same replacement rate，the influence of 19 ~ 26.5 mm angularity on unconfined compressive strength is less than that of 9.5 ~ 19 mm. The splitting strength of cement stabilized macadam base can be improved by combining the coarse aggregate with obvious edges and corners with the round coarse aggregate.