RF cosmetic devices is a popular healthcare device in the domestic home cosmetic device. However, the quality of RF cosmetic devices varies, and there is a lack of unified standard specifications for design parameters. Based on finite element analyses and COMSOL, the research constructs a three-dimensional skin model with a diaphragm, simulates the temperature distribution with changing the voltage, RF frequency of the device, the height, diameter, spacing, number and arrangement of the electrodes respectively and makes a comparative analysis. The result shows that increasing the voltage RMS or frequency can increase the maximum of temperature field; placing electrons at a distance reduces the maximum of temperature field and makes it more uniform compared to close to skin; increasing the diameter or reducing the distance between the electrodes increases the temperature; different positive and negative electrodes concentrates the heat under the fewer electrodes. Finally, this study also completed experimental measurements of temperature field distribution over time and comparative analysis with simulation. This research systematically and comprehensively discusses the influence of various parameters of RF cosmetic devices on skin temperature distribution, which provides reference for the safety and efficacy of lipolysis technology, and for the clinical application and industrialization of RF cosmetic devices.