Carrier transport property was studied in relation to microstructure for polycrystalline silicon (poly-Si) prepared from SiF4 and H2 gas mixtures at temperatures below 360°C. It was found that Hall mobility markedly increased with the increase in crystal fraction especially at crystal fractions larger than 80% and it exhibited good correlation with orientation fluctuation as well as with crystal fraction. In addition, dependence of Hall mobility on orientation fluctuation exhibited different tendency between (220) and (400) oriented poly-Si. It suggests that atomic configuration and electronic structure at grain boundaries depends on orientation structure, resulting in the different dependence of Hall mobility on orientation fluctuation. By applying hot-vapor annealing at 310°C to 1 μm-thick P-doped (400) oriented poly-Si, Hall mobility was improved from 10 cm2/Vs to 17 cm2/Vs.