Two isolates of Ganoderma lucidum (NTUG001 and NTUG002) were. used for the study of the basidiospore formation on potato dextrose agar (PDA) medium. The condition with temperature 16-24℃, optimal temperature 20℃, light density 30 1ux and wave length of light 340-500nm favored the formation of basidiospore of G. lucidum on PDA medium, providing that the successive light illumination was lasted at least for 8 days and the dikaryotic culture was at juvenile stage.