Two mycorrhizal fund CC-1,CC-2 were used to inoculate the roots of three citrus species.Anatomic investigation showed that they might be associated with the host plant to form endomycorrhiza,but there were significant differences in the debree of infection among different citrus species.At the time of four and a half months after inoculation,the rate of infection of glorious orange inoculated with CC-1 and it was found that there were mycelia on the root surface and plenty of vesicles and arbuscules in tortes.The infection rate of rough lemon inoculated with CC-2 was 7000,and there was no mycelium on the root surface,and the infection rate of Poncinus trifoliata was the minimal.