PBS was blended in a twin-screw extruder with nanoscale MMT modified with CTAB to provide PBS/MMT nanocomposite. The heat resistance, mechanical properties and rheological properties of PBS/MMT nanocomposite were studied. The results showed that when PBS was blended with nanoscale MMT modified by 5wt%, the melting point of PBS/MMT nanocomposite increased by about 2.55 ℃, the initial heat decomposition temperature increased by about 33℃. When PBS was blended with nanoscale MMT modified by 3wt%, the tensile strength of PBS/MMT nanocomposite increased by 9%, break elongating by 3%, impact strength increased by about 23%. Meanwhile, the rheological properties of PBS/MMT nanocomposite increased to certain degree compared with pure PBS.