The purple long persistence phosphor CaAl_2O_4∶Eu~(2+), Nd~(3+)was prepared by high temperature solid-state reaction method. The main factors for preparing this phosphor were studied, including the proportion of Ca and Al in the host, the content of activator, assistant activator and flux, reducing atmosphere, firing temperature and time. The optimum condition is as following: the proportion of Ca and Al at 1.0∶2.3, the content of the activator at 0.005 mol/mol, the content of the flux at 1.6% (mass fractio...