The invention discloses a bisdiglycolamide ligand and a preparation method thereof and a 
lanthanum serial / 
actinium serial separation and extraction 
system containing the bisdiglycine 
amide ligand. The extraction 
system is formed by mixing an organic phase and an aqueous phase in equal volume, wherein the organic phase contains 0.1-0.7mol / L N,N,N',N',N',N'-
hexa n-octyl-nitrilotriacetamide [NTAamide (C8)] as an extraction agent, and the aqueous phase contains the 0.005-0.02mol / L bisdiglycine 
amide ligand as a 
masking agent. The N,N,N',N',N',N'-
hexa n-octyl-nitrilotriacetamide [NTAamide] in the extraction 
system has a unique non-N-heterocyclic triangular structure, so that the 
irradiation-resistant stability of the extraction system can be greatly improved, secondary pollutants are not generated, and the 
environmental protection is facilitated; and the extraction system which takes the 
water soluble bisdiglycolamide ligand as the 
masking agent has the characteristic of more tending to be complex with 
lanthanum series, and the 
lanthanum series can be effectively masked in the aqueous phase, so that selective separation of 
actinium series and lanthanum series is realized.