High performance group III nitride semiconductor based light-emitting diodes and laser diodes most fabricated by metalorganic vapor phase epitaxy (MOVPE). In situ monitoring in MOVPE is the key process in device manufacturing. These information can be feedback to growth condition and find its mechanism. In this paper, we reported the analyzation of MOVPE growth in GaInN single layer and GaInN/GaN superlattice on GaN by in situ XRD monitoring.