A series of poly(3-hydroxybutyrate) (PHB)／poly (ethylene oxide) (PEO) blends with different compositions were studied by solid-state high-resolution 13C-NMR spectroscopy．The crystallinity

1H spin-spin relaxation time (T2) and 1H spin-lattice relaxation time in the rotating frame (T1ρ) of PHB and PEO in the blends were measured．It was found that the crystallinity of PHB may keep almost constant over the whole composition range

while that of PEO decreased dramatically with decreasing PEO content．1H T2 of the noncrystalline region of PHB increases with the increase of PEO content

indicating that the mobility of the noncrystalline resion of PHB has been enhanced．1H T1ρs of the noncrystalline PHB and PEO become close to each other as composition of the blend changes．PHB and PEO are found to be partially miscible in the noncrystalline region of the blends．The miscibility depends on the composition．The highest miscibility of noncrystalline regions of PHB and PEO is achieved when the weight content of PEO is about 20％．