This paper mainly analyzes the characteristics of the contact resistance between copper electrode and gallium-indium-tin alloy. In order to solve the fluctuation problem of the output resistance, the change rule of contact resistance with different contact stress was analyzed. Besides, the electrode coating method was explored to reduce the change of film resistance and improve contact reliability. Firstly, the theoretical model of solid-liquid contact resistance was established by theoretical derivation. According to the model, the change of contact resistance with the state of contact stress was simulated by COMSOL Multiphysics software. Secondly, in order to avoid the reaction between the copper electrode and gallium-indium-tin alloy, the copper electrode was covered by high-performance graphene films. The amount of acetylene gas as a carbon source in the graphene growth process played a very important role in the thickness and quality of the generated graphene. The copper sheet was used as the substrate in the experiment, and hydrogenated graphite was grown on its surface by low temperature chemical vapor deposition. The three-dimensional network graphene could be grown on copper substrates by pyrolysis at high temperature and rapid cooling. Different thicknesses of graphene film material growing on copper substrates were made to reduce the effect of the film on solid-liquid contact resistance. Thirdly, a contact angle measurement apparatus was used to measure the contact angle of gallium-indium-tin alloys on the copper electrode with different grown films. A self-assembled device consisted of acrylic glass, micro-ohmeter, computer and other equipment was designed to measure the contact resistance. The contact angle and the solid-liquid contact resistance with different substrate films were measured and analyzed. In terms of the contact resistance research based on contact pressure, the simulation results showed that the contact resistance decreased with the increase of contact stress. The decrease amplitude of the contact resistance was great when contact stress was small. In terms of the contact resistance research based on films, growth of high-quality graphene films could be regulated by the volume flow rate of acetylene gas during graphene growth. Four acetylene gases with the volume flow rates of 17 mL/min, 12 mL/min, 9 mL/min, 6 mL/min were selected as carbon sources. When 6 mL/min of acetylene gas was introduced, the graphene film was thinner and more uniform and the contact resistance was reduced from the 246 μΩ to 165 μΩ. In order to analyze the effect of the film, a wettability experiment using the contact angle meter was performed. The contact angles between the liquid gallium alloy and the electrodes with grown film at the four volume flow rates were respectively (124±1)°, (116±1)°, (115±1)°, (113±1)°. The experiment results showed that all the grown graphene could effectively improve the wettability, reduce the contact angle and then increase the actual contact area between the liquid metal and copper electrode. The study indicates that the growth of graphene films on the surface of copper electrodes can effectively reduce the reaction between copper and gallium and improve the stability of the solid-liquid contact resistance. What is more, the control of the contact stress on the contact surface can quantitatively change the contact resistance by orders of magnitude.