Self-reinforced composite (SRC) of PP homopolymer and Poly(propylene-co-ethylene) copolymer (= PP elastomer) had been prepared with 15 different blend ratios ranging from 100:0 to 0:100. PVDF and PP elastomer non-self-reinforced composite (n-SRC) with the same blend ratios are prepared as comparison to examine the self-reinforcement effects. Unlike the general non-self-reinforced polymer composite, SEM imagers revealed that the PP self-reinforced composite showed perfect interface with no evident phase boundaries between the two components. Still, further DSC characterization confirmed that PP homopolymer and PP elastomer exist as separate phases and thus immiscible. Tensile mechanical test on bothe SRC and n-SRC taught us that despite PP homopolymer's inferior young's modulus, tensile toughness, and ultimate strength than those of PVDF, all the properties got better in SRC case than n-SRC case. The superiority of SRC over n-SRC was especially prominent in co-continuous phase. The good interface let the SRC took advantage of PP elastomer component, allowing the composite to have strain-hardening behaviour. The strain-hardening effect contributed SRC to have better strength and tensile toughness compared to n-SRC.