An aluminum-platelet / plaster is used as a model system to investigate the orientation effects in the platelet reinforced FGM fabricated by the centrifugal solid-particle method. Every aluminum-platelets are bared from the plaster matrix, and three-dimensional (3-D) orientation for the platelets is directly observed using a 3-D orientation observation system. The effects of G number, platelet size and mean volume fraction of platelets on graded distributions of volume fraction and orientation parameter are studied. The results of the present study are compared with the previous results, and the validity of the proposed 3-D orientation observation system is discussed.