With increasing demand of environmentally friendly materials, development on biobased polymers such as polyhydroxyalkanoate (PHA) is indispensable. An unsaturated PHA, namely, poly(3-hydroxydodecanoate-co-3-hydroxy-9-decenoate), short as P(3HDD-co-3H9D), provides possibilities for functionalization. Two different strategies are explored for synthesis of PHA-graft-graphene nanocomposites with graphene content ranging from 0.2 to 1.5 wt %. Chemical structures of intermediates and products were confirmed by Fourier transform infrared spectroscopy (FTIR) and nuclear magnetic resonance (NMR). Uniform dispersion of graphene was observed in formed PHA nanocomposites under scanning electron microscopy (SEM), transmission electron microscopy (TEM), and atomic force microscopy (AFM). PHA-graft-graphene nanocomposites exhibited higher thermal degradation temperature and enhanced electricity conductivity compared with that of neat PHA. Moreover, lower critical filling content and lower electrical resistivity at same graphene content demonstrated enhanced electrical conductivity of PHA-graft-graphene nanocomposites compared with previously reported blends. The lowest electrical resistivity was 2 Omega.m in sample PHA-graft-graphene nanocomposites with approximately 1.5 wt % graphene content.