A series of Nd 0.9 Ca 0.1 Ba 2Cu 3O 6+x samples with different oxygen content were fabricated by the solid state reaction method and thermal treated under different conditions. Thephase structures of these samples have been verified with XRD method. The structural transition from tetragonal to orthorhombic phase appeares with increasing the oxygen content. Furthermore, the characteristics of structural phase transition were investigated with the infrared absorbance spectra methid. The variations of 642 cm -1 , 578 cm -1 , 538 cm -1 peaks are corresponding to the structure transition induced by the oxygen content. And the relation between the structure and the superconductivity has been discussed.