The invention discloses a rice heavy metal absorption blocking agent and a use method thereof. The blocking agent includes one or more effective components of alpha-ketoglutarate, glycerol and oxaloacetic acid. The aim of preventing heavy metal from being absorbed and transferred to rice can be achieved through leaf surface spraying in the rice tillering period, heading period and/or postulation period. The contents of lead, cadmium and other heavy metal polluting rice in rice fields can be remarkably reduced, and rice produced in rice fields slightly or intermediately polluted by heavy metal meets the food safety standard. The effective spraying concentration of the blocking agent is low, the blocking agent can be sprayed after being mixed with pesticides for preventing and treating rice diseases and pests, and cost is low.