Block copolymers not only combine properties of different segments but also generate new application prospects.Poly(α-amino ac-id)-b-poly(tetrahydrofuran)-b-poly(α-amino acid) (PAA-PTHF-PAA) is one of the copolymers.In this contribution,di-hydroxyl-ended HO-PTHF-OH is transferred into di-oxyamino-ended H2NO-PTHF-ONH2 quantitatively,which is used as a macroinitiator to polymerize sarcosine N-thiocarboxyanhydride (Sar-NTA) and N-phenyoxycarbonyl N-ε-carbobenzyloxy-D-lysine (ZDL-NPC).Well-defined triblock PAA-NHO-PTHF-ONH-PAA is produced with high molecular weight (up to 25.3 kg/mol) and narrow dispersity.The amphiphilic PSar-NHO-PTHF-ONH-PSar (STS) self-assembles into micelles with uniform diameters of 30-40 nm according to DLS.Owing to oxy-gen amide groups inside the backbone of these copolymers,the polyether-poly(amino acid)s block copolymers are cleavable under an acidic environment and therefore have potential applications in smart biomedicine and engineering.