<p>In this work, the influence of liquid-phase exfoliated graphene (G) on the melt memory effect of isotactic polypropylene (iPP) was investigated. The nucleation ability of both the melt ordered structure and graphene for iPP crystallization was examined for comparison. The results indicated that liquid-phase exfoliated graphene has excellent heterogeneous nucleation ability. With the addition of only 0.5 wt.% graphene, the crystallization peak temperature of iPP is increased by 11.3&#xa0;°C. However, in contrast to graphene, melt ordered structure demonstrates more significant nucleation ability. The introduction of graphene brings about weakened melt memory effect of iPP, as evidenced by the diminished temperature width of Domain II for the composite. These findings are consistent with the results obtained from the nonisothermal crystallization kinetics. Dynamic rheology and in-situ Fourier transform infrared spectroscopy measurements revealed that depressed thermal stability of ordered structure caused by the presence of graphene is responsible for weakened melt memory effect of iPP.</p>