Polypropylene copolymers (CPP) containing β-nucleating agent were investigated by differential scanning calorimetry (DSC), wide-angle X-ray diffraction (WAXD) and polarizing light microscopy (PLM). The results show that high content of β-phase crystals can also be formed for CPPs. Like PP homopolymers, the CPPs also have a most favorable temperature near 132C for β-phase crystal growth. The crystallization rate of CPPs containing β-nucleating agent (β-CPP) is much greater than that of PP homopolymer containing β-nucleating agent (β-PP homopolymer). The observation of spherulite morphology of β-CPP and β-PP homopolymer shows that the spherulites of β-CPP are more imperfect than those ofβ-PP homopolymer.