Abstract: Rare earths(RE) in agriculture has great economic benefits,but environmental security problems emerge in the long-run.The effects of rare earths on edaphons,plants and animals were measured by the level of RE ecotoxicity.It is observed that RE changes edaphon population structure,population numbers and their soil enzyme activity;affects plant growth,biological physiology and RE accumulation in plant;and damages human reproductive system and health,liver and children's intelligence.It is concluded that RE is toxic to biota,and could directly affect biological processes,or indirectly affect biological processes through food chain.It is recommended that the effects of RE on environment,agriculture and man should be further investigated.