We performed nanoXRD measurements and TEM observations for strained SiGe spintronics devices to investigate the relationship among spin transport, crystal structure, and local strain distribution. Our nanoXRD results quantitatively proved the existence of appropriate strain in the SiGe channel in the device with spin signals at room temperature. On the other hand, in the device with almost no spin signals, relaxation of strain and local change in crystallinity were detected, which are attributed to lattice defects in the channel layers. The present results demonstrate the capability of non-destructive nanoXRD methods for quantitative strain and crystallinity analysis in real device structures.