The invention provides an aminophosphonate compound, and application thereof in extraction of lithium in an alkaline solution containing lithium ions, and relates to the technical field of metal ion extraction. The structure of the aminophosphonate compound is as shown in formula (I). In the formula (I), R1 is a straight chain of C1-C20 straight-chain or branched-chain alkyl, C1-C20straight-chain or branched-chain alkoxy, or C6-C10 aryl; R2 and R3 are respectively and independently hydrogen, C1-C10 straight-chain or branched-chain alkyl, C1-C10 alkoxy, or C6-C10 aryl; R < 3 > is hydrogen, C1-C10 straight-chain or branched-chain alkyl, C1-C10 alkoxy, or C6-C10 aryl; R4 and R are respectively and independently C1-C10 straight-chain or branched-chain, saturated or unsaturated, substituted or unsubstituted alkyl groups, or C6-C10 aryl; and n is an integer of 1-4. The aminophosphonate compound can be widely applied to extraction of lithium ions in the alkaline solution containing the lithium ions.