As a good film electrode material for supercapacitor (Ru-Sn)O2·nH2O film was deposited on tantalum foils with aqueous solution of (Ru-Sn)Clx as reservoir by galvanostatic-differential pulse voltammetry and heat treatment. The surface morphology, phase transition of precursor (Ru-Sn)Clx to amorphous (Ru-Sn)O2·nH2O and capacitance of the film were studied by scanning electron microscope (SEM), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and electrochemical analyzer, respectively. Results show that the precursor (Ru-Sn)Clx transforms into (Ru-Sn)O2·nH2O film by the proper heat treatment, and the adhesive force of the film with Ta substrate is improved significantly which is measured to be 12.3 MPa. The binding force is improved with addition of SnCl2 into solution. With more addition of SnCl2, the surface mass per unit area is increased; the capacitance of the film per unit area is increased at first and then decreased gradually with a maximum value of 1.9 F/cm2 while the special capacitance drops continuously