Dependence of Mg doped InN characteristics on the rapid thermal annealing (RTA) temperature is investigated. The mosaic tilt, twist and correlation lengths of InN film are determined by using X-ray diffraction (XRD) symmetrical and asymmetrical reflections as well as reciprocal spacing mapping (RSM), which will then lead to the screw and edge dislocations. Comparing with the dislocations and mobility in different RTA temperatures, the crystal qualities are greatly improved at 400 ℃. We suggest that Mg atoms are activated by the RTA treatment, along with the reduction of carrier concentration. At the same time, N vacancies, which act as donors, are partly compensated when annealing in N2 atmosphere, leading to the reduction of defects and dislocations as well as carrier concentration. Such results also corroborate with the full width of half maximum (FWHM) of ω scans of InN (002) plane.