Radiofrequency heating is widely used in medical aesthetics, which essentially achieves the contraction of collagen fibers in the dermis by increasing its temperature. The paper aimed to study the selective and controllable mechanism for the temperature field in 0.02 kg ex-vivo pig skin samples obtained from the 25 kg Bama pig under radiofrequency heating by the finite element method and relevant experiments. A heating model of pig skin was constructed at 4 MHz with a mixed heating mode of fixed-point and reciprocating sliding. Based on the mixed heating, the dermis was heated preferentially and uniformly due to its high electrical conductivity and thermal conductivity compared to other tissue layers. It allowed the dermis temperature 55.1 ℃ to remain at a dynamic plateau period with an error of 0.1 ℃, and the mean specific absorption rate across the entire pig was under 2 W/kg within 30 s in this period. The verification experiment on the pig skin samples under the same conditions showed consistent temperature distributions between the model and experiment, and the dermis collagen fibers structure was clear without tissue damage. The research results provide useful guidance for radiofrequency application practitioners to selectively control skin temperature distributions.