We observed the growth of the Ga0.80In0.20N (2 nm)/GaN (3 nm) superlattice(SL) structure by in situ X-ray diffraction(XRD) monitoring. The satellite peaks from the -1st to the +1st order can be obtained from these in situ XRD spectrums. From the full width at half maximums(FWHMs) of the 0th and -1st satellite peaks as a function of the SL periods, we observed a clear trend in each FWHM. It was found that by analyzing this trend along with florescence microscopic and transmission electron microscopic analysis, an analysis of the In segregation and misfit dislocation are possible. Accordingly, if we employ in situ XRD under various growth conditions, the optimization of the growth conditions will become easier because it would be possible to determine the number of periods at which In segregation and misfit dislocation increases by only one growth procedure. (C) 2014 Published by Elsevier B.V.