$YBa_2Cu_3O_{7-x}$ (YBCO) superconducting films were fabricated on Cu plates for simplicity of the process using Cu-free $Y_2O_3$ and $BaCO_3$ mixed powders (attrition-milled) by screen-printing method. It was reported that CuO, which deteriorates superconducting property of YBCO films, was formed on the surface of the films. As amount of Cu element supplied from Cu plates can not be controlled, we must find mixed ratio of Cu-free powders to suppress CuO formation on the surface of the films. As the mixed mole ratios of $Y_2O_3$ to $BaCO_3$ were varied from 1/2 to 1/8, Cu-free films screen-printed on Cu plates were heat-treated to form YBCO phase at 980℃ for 17sec in the tube furnace. The films were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive spectroscopy (EDS) analysis. We found that CuO was not formed on the surface of the films in 1/2 ratio. As Cu-free films mixed in 1/2 ratio were heat-treated at 980$^\circ$C for 17sec, Y211 and Ba-Cu oxide were formed in the films. According to the literature survey, we reheat-treated at 930℃ for 9min 30sec to form superconducting YBCO films. As oxygen annealing was done at 450℃ for 1h, the superconducting property of the films was improved.
