Self-assembly behavior of a double-bond-based amphiphilic graft copolymer consisting of hydrophobic polyallene backbone and hydrophilic poly(ethylene glycol) side chains in tetrahydrofuran (THF)/water was investigated. Polyallene backbone was first prepared via living coordination polymerization of 6-methyl-1,2-heptadien-4-ol (MHDO) initiated by [(eta(3)-allyl)NiOCOCF3](2). The targeted amphiphilic graft copolymer with relative narrow molecular weight distribution (M-w/M-n = 1.22) was synthesized by the coupling reaction between the pendant hydroxyls of the backbone and acyl chloride end group of poly (ethylene glycol) via the grafting-onto approach. The critical micelle concentration (cmc) was determined by the fluorescence probe technique. Micelle morphologies could be well tuned by water content, initial copolymer content, and ion strength. In particular, this kind of achiral copolymer could aggregate to form chiral helical nanostructures under given conditions.