A method for enriching lithium from a lithium clay, comprising the following steps: crushing the lithium clay to produce the minus 1 mm size fraction raw ore, wherein the mass proportion of the minus 0.15 mm size fraction is ≥ 60%; flotating the minus 1 mm raw ore, adding an aqueous solution of ferric sulfate or ferric nitrate, and stirring evenly, then adding a pH regulator to adjust a pH value of the system to be 9-10, then adding an aqueous solution of sodium oleate and an aqueous solution of cocoamine, stirring evenly, and then flotating to obtain a rough concentrate and a rough tailing; flotating the rough concentrate, and adding a pH regulator to adjust a pH value of the system to be 9-10, and stirring evenly, then adding an aqueous solution of sodium oleate and an aqueous solution of cocoamine, stirring evenly, and then flotating to obtain a concentrate A and a cleaned tailing; mixing the rough tailing in step with the cleaned tailing in step and performing a wet ball milling to obtain a tailing A with a mass ratio of a minus 0.074 mm tailing ≥ 80%; flotating the tailing A, adding an aqueous solution of ferric sulfate or ferric nitrate, stirring evenly, adding a pH regulator to adjust a pH value to be 9-10, then adding an aqueous solution of sodium hexametaphosphate, stirring evenly, adding an aqueous solution of sodium oleate and an aqueous solution of cocoamine, stirring evenly, and then flotating to obtain a reground rough concentrate and a reground rough tailing; flotating the reground rough concentrate, adding a pH regulator to adjust a pH value to be 9-10, then adding an aqueous solution of sodium hexametaphosphate, stirring evenly, adding an aqueous solution of sodium oleate and an aqueous solution of cocoamine, stirring evenly, and then flotating to obtain a concentrate B; flotating the reground rough tailing, adding a pH regulator to adjust a pH value to be 9-10, then adding an aqueous solution of sodium oleate and an aqueous solution of cocoamine, stirring evenly, and then flotating to obtain a cleaned tailing B; and using the concentrate A and the concentrate B as a final concentrate, and using the cleaned tailing B as a final tailing. crushing the lithium clay to produce the minus 1 mm size fraction raw ore, wherein the mass proportion of the minus 0.15 mm size fraction is ≥ 60%; flotating the minus 1 mm raw ore, adding an aqueous solution of ferric sulfate or ferric nitrate, and stirring evenly, then adding a pH regulator to adjust a pH value of the system to be 9-10, then adding an aqueous solution of sodium oleate and an aqueous solution of cocoamine, stirring evenly, and then flotating to obtain a rough concentrate and a rough tailing; flotating the rough concentrate, and adding a pH regulator to adjust a pH value of the system to be 9-10, and stirring evenly, then adding an aqueous solution of sodium oleate and an aqueous solution of cocoamine, stirring evenly, and then flotating to obtain a concentrate A and a cleaned tailing; mixing the rough tailing in step with the cleaned tailing in step and performing a wet ball milling to obtain a tailing A with a mass ratio of a minus 0.074 mm tailing ≥ 80%; flotating the tailing A, adding an aqueous solution of ferric sulfate or ferric nitrate, stirring evenly, adding a pH regulator to adjust a pH value to be 9-10, then adding an aqueous solution of sodium hexametaphosphate, stirring evenly, adding an aqueous solution of sodium oleate and an aqueous solution of cocoamine, stirring evenly, and then flotating to obtain a reground rough concentrate and a reground rough tailing; flotating the reground rough concentrate, adding a pH regulator to adjust a pH value to be 9-10, then adding an aqueous solution of sodium hexametaphosphate, stirring evenly, adding an aqueous solution of sodium oleate and an aqueous solution of cocoamine, stirring evenly, and then flotating to obtain a concentrate B; flotating the reground rough tailing, adding a pH regulator to adjust a pH value to be 9-10, then adding an aqueous solution of sodium oleate and an aqueous solution of cocoamine, stirring evenly, and then flotating to obtain a cleaned tailing B; and using the concentrate A and the concentrate B as a final concentrate, and using the cleaned tailing B as a final tailing.