The miscibility, crystallization behavior and morphological structure of PHB/PMAblends have been studied by the differential scanning calorimeter (DSC) and polarized opticalndcroscopy (POM). The chemical repeat units of the two components of the blend are isomers.The results indicate that PHB and PMA are ndscible in the melt. The addition of PMA into PHBresults in a depression in the spherulite growth rate of PHB. With increasing PMA content in theblends, the texture of PHB spherulite becomes more open.