In this article, we have employed GSAS software to do Reitveld profile refinement on XRD patterns from H-T_c superconductor powder YBa2_-xK_xCu₃O_7-y (0<x,y<1) samples. Increasing the Potassium doping content of the sample, x, causes some changes in the XRD patterns such as creating new peaks and also deteriorating of goodness of the refinement, χ². On the other hand, substituting of K instead of Ba led to oxygen depletion and also lowering the Ba (K) plane position along the Z direction (||c). The structural phase ratio of tetragonal to orthorhombic increased and it means that the superconductivity exist even in samples with dominant tetragonal phase.