Superconductive samples with compositions of YbBa2Cu3F2xO7-x-δ (0≤x≤1) have been prepared. The variations of Tc, lattice constants and cell volume with the fluorine dose have been described. We report an experimental observation of an increase of Tc with a decrease of the oxygen content in the YbBa2Cu3F2xO7-x-δ (0 ≤x≤1). Therefore with the content of oxygen increasing, the lattice constants and cell volume of the superconducter become larger. The higher Tc, the larger is the velue of lattice constants (b-a) of the orthorhombic structure. It has been shown that the M-Cu-O or Cu-O part of the systems may have an essential role or the superconductivity.